Hello,
this driver implements backlight control on Dell laptops
which use SMI for changing brightness levels.
The driver is INCOMPLETE since it is unable to probe some required parameters
in order to perform backlight control. Such parameters are found in a Dell
proprietary DMI table which should be parsed. For now external tools may be
used to find these parameters by hand. So if you intend to try this out,
FIRST write your laptop model parameters correctly inside the source code
as explained in Documentation/dell-laptop.txt.
Parts of this driver may also be used to provide additional functionalities
similarly to the drivers/misc/*-laptop.c drivers.
regards,
jacopo antonello
******************************* diff follows
--- linux-2.6.23.1/Documentation/dell-laptop.txt 1970-01-01 01:00:00.000000000 +0100
+++ b/Documentation/dell-laptop.txt 2007-10-28 13:45:24.000000000 +0100
@@ -0,0 +1,105 @@
+This driver is EXPERIMENTAL, use it at YOUR OWN RISK.
+
+BEFORE TRYING THIS DRIVER OUT:
+You MUST FILL IN your laptop parameters in the source code. This
+driver is not capable of probing these parameters on its own.
+
+The parameters involved are:
+- IO Port address
+- IO command code
+- Location
+
+These parameters depend (hopefully) on the model of your laptop. Such information
+is found in a private Dell DMI table. You may use dmidecode or libsmbios' dumpCmos
+(http://linux.dell.com/libsmbios/download/libsmbios/). The latter is best since
+it DECODES COMPLETELY Dell's tokens.
+
+******************************************************* WITH LIBSMBIOS
+root@here:~# dumpCmos | grep 0x007d
+and you will get a line like the following...
+DMI type 0xda Handle 0xda00 CmdIO Port 0x00b2 CmdIO Code 0x0d Type 0x007d Location 0x0000 value 0000
+
+open dell-laptop.c and write the parameters accordingly under the probe_smi_params()
+function
+
+static int probe_smi_params(void)
+{
+ /*
+ * these should be probed by parsing Dell's CMOS table (dmi type 0xda)
+ */
+ smi_params.cmdio_port = 0x00b2; /* libsmbios' dumpCmos CmdIO Port */
+ smi_params.cmdio_code = 0x0d; /* libsmbios' dumpCmos CmdIO Code */
+ smi_params.backlight_location = 0; /* set to dumpCmos Location */
+ smi_params.backlight_value = 0; /* set to dumpCmos Value (unused for backlight) */
+
+ return 0;
+}
+**********************************************************************
+
+******************************************************* WITH DMIDECODE
+(this is HAND parsing!!)
+dmidecode & look for table type 218
+
+Handle 0xDA00, DMI type 218, 125 bytes
+OEM-specific Type
+ Header and Data:
+ DA 7D 00 DA B2 00 0D 5F 0F 37 40 7D 00 00 00 00
+ 00 7E 00 02 00 00 00 40 00 04 00 01 00 41 00 04
+ 00 00 00 90 00 05 00 00 00 91 00 05 00 01 00 92
+ 00 05 00 02 00 45 01 45 01 01 00 44 01 44 01 00
+ 00 00 80 00 80 01 00 00 A0 00 A0 01 00 05 80 05
+ 80 01 00 76 01 76 01 01 00 75 01 75 01 01 00 01
+ F0 01 F0 00 00 02 F0 02 F0 00 00 03 F0 03 F0 00
+ 00 04 F0 04 F0 00 00 FF FF 00 00 00 00
+
+now you have:
+1 byte DA (table type)
+1 byte 7D (table size)
+2 bytes 00 DA (handle)
+2 bytes B2 00 (cmdio port address (swapped) )
+1 byte 0D (cmdio code)
+4 bytes 5F 0F 37 40 (supported commands ?)
+
+after that you have triplets terminated by FF FF 00 00 00 00
+in the form (type, location, value)
+
+type | loc | val
+7D 00|00 00|00 00
+7E 00|02 00|00 00
+40 00|04 00|01 00
+41 00|04 00|00 00
+90 00|05 00|00 00
+91 00|05 00|01 00
+92 00|05 00|02 00
+45 01|45 01|01 00
+44 01|44 01|00 00
+00 80|00 80|01 00
+00 A0|00 A0|01 00
+05 80|05 80|01 00
+76 01|76 01|01 00
+75 01|75 01|01 00
+01 F0|01 F0|00 00
+02 F0|02 F0|00 00
+03 F0|03 F0|00 00
+04 F0|04 F0|00 00
+end
+FF FF|00 00|00 00
+
+you can read the Location field in type 0x007d (swapped 7D 00)
+
+then modify dell-laptop.c accordingly (remember to swap the lsb with the msb
+n the port address also!)
+
+static int probe_smi_params(void)
+{
+ /*
+ * these should be probed by parsing Dell's CMOS table (dmi type 0xda)
+ */
+ smi_params.cmdio_port = 0x00b2; /* libsmbios' dumpCmos CmdIO Port */
+ smi_params.cmdio_code = 0x0d; /* libsmbios' dumpCmos CmdIO Code */
+ smi_params.backlight_location = 0; /* set to dumpCmos Location */
+ smi_params.backlight_value = 0; /* set to dumpCmos Value (unused for backlight) */
+
+ return 0;
+}
+**********************************************************************
--- linux-2.6.23.1/drivers/misc/Makefile 2007-10-12 18:43:44.000000000 +0200
+++ b/drivers/misc/Makefile 2007-10-28 13:45:24.000000000 +0100
@@ -15,3 +15,4 @@ obj-$(CONFIG_SGI_IOC4) += ioc4.o
obj-$(CONFIG_SONY_LAPTOP) += sony-laptop.o
obj-$(CONFIG_THINKPAD_ACPI) += thinkpad_acpi.o
obj-$(CONFIG_EEPROM_93CX6) += eeprom_93cx6.o
+obj-$(CONFIG_DELL_LAPTOP) += dell-laptop.o
--- linux-2.6.23.1/drivers/misc/dell-laptop.h 1970-01-01 01:00:00.000000000 +0100
+++ b/drivers/misc/dell-laptop.h 2007-10-28 13:45:24.000000000 +0100
@@ -0,0 +1,116 @@
+/*
+ * dell-laptop.h - Dell laptop extras
+ *
+ *
+ * Copyright (C) 2007 Jacopo Antonello <[email protected]>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+ * 02110-1301, USA.
+ */
+
+#ifndef _DELL_LAPTOP_H_
+#define _DELL_LAPTOP_H_
+
+#include <linux/device.h>
+#include <linux/sysfs.h>
+#include <linux/types.h>
+
+#define SMI_CMD_MAGIC 0x534D4931 /* "SMI1" */
+#define SMI_CMD_ECX 0x42534931 /* "BSI1" */
+
+#define SMI_CMD_SIZE sizeof(struct smi_cmd)
+#define SMI_BUF_SIZE sizeof(struct smi_cmd_buffer)
+#define SMI_IF_SIZE (SMI_CMD_SIZE + SMI_BUF_SIZE)
+
+#define SMI_CLASS_READ_SETTING 0
+#define SMI_CLASS_WRITE_SETTING 1
+
+#define SMI_SELECT_BATTERY 1
+#define SMI_SELECT_AC 2
+
+#define BRIGHTNESS_BATTERY (SMI_SELECT_BATTERY - 1)
+#define BRIGHTNESS_AC (SMI_SELECT_AC - 1)
+
+#define DELL_TABLE_DA 0xda
+#define DELL_CALLIF_ID_BACKLIGHT 0x007d
+
+#define DRIVER_NAME "dell-laptop"
+#define DRIVER_DESCRIPTION "Dell laptop extras"
+#define DRV_PFX "dell-laptop: "
+
+struct smi_cmd {
+ __u32 magic;
+ __u32 ebx;
+ __u32 ecx;
+ __u16 command_address;
+ __u8 command_code;
+ __u8 reserved;
+ /* __u8 command_buffer[1]; */
+} __attribute__ ((packed));
+
+struct smi_cmd_buffer
+{
+ __u16 smi_class;
+ __u16 smi_select;
+
+ __u32 cbARG1;
+ __u32 cbARG2;
+ __u32 cbARG3;
+ __u32 cbARG4;
+
+ __s32 cbRES1;
+ __s32 cbRES2;
+ __s32 cbRES3;
+ __s32 cbRES4;
+} __attribute__ ((packed));
+
+struct smi_params_t {
+ struct mutex lock;
+
+ u16 cmdio_port;
+ u8 cmdio_code;
+ u32 supported_cmds;
+
+ u16 backlight_location;
+ u16 backlight_value;
+};
+
+enum backlight_drive_mode {
+ BACKLIGHT_DRIVE_BOTH,
+ BACKLIGHT_DRIVE_CURRENT,
+ BACKLIGHT_DRIVE_BATTERY,
+ BACKLIGHT_DRIVE_AC
+};
+
+static struct platform_driver dell_driver = {
+ .driver = {
+ .name = DRIVER_NAME,
+ .owner = THIS_MODULE,
+ }
+};
+
+static struct backlight_device *dell_backlight_dev;
+static struct platform_device *dell_platform_dev;
+
+static u8 *smi_if;
+static dma_addr_t smi_handle;
+
+static struct smi_params_t smi_params;
+
+static enum backlight_drive_mode backlight_drive_mode;
+static u32 brightness_vals[2];
+static u32 brightness_min_value = 0;
+
+#endif
--- linux-2.6.23.1/drivers/misc/dell-laptop.c 1970-01-01 01:00:00.000000000 +0100
+++ b/drivers/misc/dell-laptop.c 2007-10-28 13:45:24.000000000 +0100
@@ -0,0 +1,651 @@
+/*
+ * dell-laptop.c - Dell laptop extras
+ *
+ * This driver implements only backlight control for now.
+ * This driver assumes that you are not using bios password
+ * protection and does not work if it is enabled.
+ *
+ * This driver is EXPERIMENTAL and it is not yet complete. In
+ * particular it lacks proper probing for the hardware
+ * it is meant to control.
+ *
+ * WARNING: you MUST fill in your laptop CMOS parameters, by
+ * modifying the default values found in probe_smi_params().
+ * Failing to do so could cause unpredictable effects on your
+ * laptop. In order to do this you may use the dumpCmos utility
+ * found in libsmbios (http://linux.dell.com/libsmbios/download/libsmbios/)
+ *
+ * Parts of this driver were inspired by dcdbas.c and libsmbios
+ * (http://linux.dell.com/libsmbios/download/libsmbios/)
+ *
+ * Copyright (C) 2007 Jacopo Antonello <[email protected]>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+ * 02110-1301, USA.
+ */
+
+#define DRIVER_VERSION "0.1"
+
+/*
+ * Changelog:
+ * 2007-12-22 0.01 initial release
+ * support for backlight on Dell M70 laptops
+ * TODO fix framebuffer support
+ * TODO add cmos token lookup
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/dma-mapping.h>
+#include <linux/mutex.h>
+#include <linux/sched.h>
+#include <linux/backlight.h>
+
+#include "dell-laptop.h"
+
+MODULE_DESCRIPTION(DRIVER_DESCRIPTION " (version " DRIVER_VERSION ")");
+MODULE_VERSION(DRIVER_VERSION);
+MODULE_AUTHOR("jacopo antonello <jack at antonello.org>");
+MODULE_LICENSE("GPL");
+
+/* --------------------------------------------------------------------------
+ * smi
+ * -------------------------------------------------------------------------- */
+
+static int probe_smi_params(void)
+{
+ /*
+ * these should be probed by parsing Dell's CMOS table (dmi type 0xda)
+ */
+ smi_params.cmdio_port = 0x00b2; /* libsmbios' dumpCmos CmdIO Port */
+ smi_params.cmdio_code = 0x0d; /* libsmbios' dumpCmos CmdIO Code */
+ smi_params.backlight_location = 0; /* set to dumpCmos Location */
+ smi_params.backlight_value = 0; /* set to dumpCmos Value (unused for backlight) */
+
+ return 0;
+}
+
+static int trigger_smi(u16 ioport, u8 iocode, struct smi_cmd_buffer *parms)
+{
+ struct smi_cmd *cmd = (struct smi_cmd *)smi_if;
+ struct smi_cmd_buffer *buf = (struct smi_cmd_buffer *)(smi_if + SMI_CMD_SIZE);
+ cpumask_t old_mask;
+ int ret = 0;
+
+ mutex_lock(&smi_params.lock);
+
+ cmd->magic = SMI_CMD_MAGIC;
+ cmd->ebx = (u32)virt_to_phys(buf);
+ cmd->ecx = SMI_CMD_ECX;
+ cmd->command_address = ioport; /* libsmbios' dumpCmos CmdIO Port */
+ cmd->command_code = iocode; /* libsmbios' dumpCmos CmdIO Code */
+ cmd->reserved = 0;
+
+ buf->smi_class = parms->smi_class; /* 0 read, 1 write */
+ buf->smi_select = parms->smi_select; /* 1 battery mode, 2 ac mode */
+
+ buf->cbARG1 = parms->cbARG1; /* set to dumpCmos Location */
+ buf->cbARG2 = parms->cbARG2;
+ buf->cbARG3 = parms->cbARG3;
+ buf->cbARG4 = parms->cbARG4;
+
+ buf->cbRES1 = parms->cbRES1; /* set to -1 to tell errors */
+ buf->cbRES2 = parms->cbRES2;
+ buf->cbRES3 = parms->cbRES3;
+ buf->cbRES4 = parms->cbRES4;
+
+ /* dcdbas.c */
+ old_mask = current->cpus_allowed;
+ set_cpus_allowed(current, cpumask_of_cpu(0));
+ if (smp_processor_id() != 0) {
+ dev_dbg(&dell_backlight_dev->dev, "%s: failed to get CPU 0\n",
+ __FUNCTION__);
+ ret = -EBUSY;
+ goto out;
+ }
+
+ asm volatile (
+ "outb %b0,%w1"
+ : /* no output args */
+ : "a" (cmd->command_code),
+ "d" (cmd->command_address),
+ "b" (cmd->ebx),
+ "c" (cmd->ecx)
+ : "memory"
+ );
+
+ switch( buf->cbRES1 ) {
+ case -6: /* output buffer not large enough */
+ case -5: /* output buffer format error */
+ case -3: /* unhandled smi call */
+ case -2: /* unsupported smi call */
+ case -1: /* bios returned error for smi call */
+ ret = -EBUSY;
+ printk(KERN_WARNING DRV_PFX "SMI failed\n");
+ goto out;
+ }
+
+ /* copy back results */
+ parms->smi_class = buf->smi_class;
+ parms->smi_select = buf->smi_select;
+
+ parms->cbARG1 = buf->cbARG1;
+ parms->cbARG2 = buf->cbARG2;
+ parms->cbARG3 = buf->cbARG3;
+ parms->cbARG4 = buf->cbARG4;
+
+ parms->cbRES1 = buf->cbRES1;
+ parms->cbRES2 = buf->cbRES2;
+ parms->cbRES3 = buf->cbRES3;
+ parms->cbRES4 = buf->cbRES4;
+
+out:
+ set_cpus_allowed(current, old_mask);
+
+ mutex_unlock(&smi_params.lock);
+
+ return ret;
+}
+
+/* --------------------------------------------------------------------------
+ * brightness
+ * -------------------------------------------------------------------------- */
+
+/* use read_brightness(SMI_SELECT_*) */
+static void read_brightness(int select)
+{
+ struct smi_cmd_buffer buf = {
+ .smi_class = SMI_CLASS_READ_SETTING,
+ .smi_select = select,
+
+ .cbARG1 = smi_params.backlight_location,
+ .cbARG2 = 0,
+ .cbARG3 = 0,
+ .cbARG4 = 0,
+
+ .cbRES1 = -1,
+ .cbRES2 = 0,
+ .cbRES3 = 0,
+ .cbRES4 = 0
+ };
+
+ if (trigger_smi(smi_params.cmdio_port, smi_params.cmdio_code, &buf)) {
+ printk(KERN_ERR DRV_PFX "unable to read brightness levels\n");
+ return;
+ }
+
+ brightness_vals[select - 1] = buf.cbRES2;
+ printk(KERN_DEBUG DRV_PFX " brightness_vals[ %d ]: %d\n", select - 1,
+ brightness_vals[select - 1]);
+ brightness_min_value = buf.cbRES3;
+ printk(KERN_DEBUG DRV_PFX " brightness_min_value: %d\n", brightness_min_value);
+ dell_backlight_dev->props.max_brightness = buf.cbRES4;
+ printk(KERN_DEBUG DRV_PFX " props.max_brightness: %d\n",
+ dell_backlight_dev->props.max_brightness);
+}
+
+/* use write_brightness(SMI_SELECT_*) */
+static void write_brightness(int select)
+{
+ struct smi_cmd_buffer buf = {
+ .smi_class = SMI_CLASS_WRITE_SETTING,
+ .smi_select = select,
+
+ .cbARG1 = smi_params.backlight_location,
+ .cbARG2 = brightness_vals[select - 1],
+ .cbARG3 = 0,
+ .cbARG4 = 0,
+
+ .cbRES1 = -1,
+ .cbRES2 = 0,
+ .cbRES3 = 0,
+ .cbRES4 = 0
+ };
+
+ if (trigger_smi(smi_params.cmdio_port, smi_params.cmdio_code, &buf)) {
+ printk(KERN_ERR DRV_PFX "unable to write brightness\n");
+ return;
+ }
+
+ if (buf.cbRES2 != brightness_vals[select - 1]) {
+ printk(KERN_ERR DRV_PFX "brightness value unchanged\n");
+ }
+
+ brightness_vals[select - 1] = buf.cbRES2;
+ printk(KERN_DEBUG DRV_PFX " brightness_vals[ %d ]: %d\n", select - 1,
+ brightness_vals[select - 1]);
+}
+
+static int dell_backlight_update_status(struct backlight_device *dev)
+{
+ dev->props.brightness = dev->props.brightness < brightness_min_value ?
+ brightness_min_value : dev->props.brightness > dev->props.max_brightness ?
+ dev->props.max_brightness : dev->props.brightness;
+
+ switch(backlight_drive_mode) {
+ case BACKLIGHT_DRIVE_BOTH:
+ brightness_vals[BRIGHTNESS_BATTERY] = dev->props.brightness;
+ brightness_vals[BRIGHTNESS_AC] = dev->props.brightness;
+ write_brightness(SMI_SELECT_BATTERY);
+ write_brightness(SMI_SELECT_AC);
+ break;
+ case BACKLIGHT_DRIVE_AC:
+ brightness_vals[BRIGHTNESS_AC] = dev->props.brightness;
+ write_brightness(SMI_SELECT_AC);
+ break;
+ case BACKLIGHT_DRIVE_BATTERY:
+ brightness_vals[BRIGHTNESS_BATTERY] = dev->props.brightness;
+ write_brightness(SMI_SELECT_BATTERY);
+ break;
+ case BACKLIGHT_DRIVE_CURRENT:
+ printk(KERN_ERR DRV_PFX "BACKLIGHT_DRIVER_CURRENT unimplemented\n");
+ default:
+ printk(KERN_ERR DRV_PFX "unknown backlight_drive_mode\n");
+ }
+
+ return dev->props.brightness;
+}
+
+static void update_from_brightness_vals(void)
+{
+ switch(backlight_drive_mode) {
+ case BACKLIGHT_DRIVE_BOTH:
+ dell_backlight_dev->props.brightness = brightness_vals[BRIGHTNESS_BATTERY];
+ if (brightness_vals[BRIGHTNESS_AC] !=
+ brightness_vals[BRIGHTNESS_BATTERY] ) {
+ brightness_vals[BRIGHTNESS_AC] = brightness_vals[BRIGHTNESS_BATTERY];
+ write_brightness(SMI_SELECT_AC); /* force ac to the same value */
+ }
+ break;
+ case BACKLIGHT_DRIVE_AC:
+ dell_backlight_dev->props.brightness = brightness_vals[BRIGHTNESS_AC];
+ break;
+ case BACKLIGHT_DRIVE_BATTERY:
+ dell_backlight_dev->props.brightness = brightness_vals[BRIGHTNESS_BATTERY];
+ break;
+ case BACKLIGHT_DRIVE_CURRENT:
+ printk(KERN_ERR DRV_PFX "BACKLIGHT_DRIVER_CURRENT unimplemented\n");
+ default:
+ printk(KERN_ERR DRV_PFX "unknown backlight_drive_mode\n");
+ }
+}
+
+static int dell_backlight_get_brightness(struct backlight_device *dev)
+{
+ /* is locking needed? */
+ mutex_lock(&dell_backlight_dev->update_lock);
+
+ read_brightness(SMI_SELECT_BATTERY);
+ read_brightness(SMI_SELECT_AC);
+
+ update_from_brightness_vals();
+
+ mutex_unlock(&dell_backlight_dev->update_lock);
+
+ return dev->props.brightness;
+}
+
+static struct backlight_ops dell_backlight_ops = {
+ .update_status = dell_backlight_update_status,
+ .get_brightness = dell_backlight_get_brightness
+};
+
+static int dell_backlight_init(struct device *dev)
+{
+ dell_backlight_dev = backlight_device_register(
+ "dell-laptop",
+ NULL,
+ NULL,
+ &dell_backlight_ops);
+
+ if (IS_ERR(dell_backlight_dev)) {
+ dell_backlight_dev = NULL;
+ return PTR_ERR(dell_backlight_dev);
+ }
+
+ backlight_drive_mode = BACKLIGHT_DRIVE_AC;
+
+ dell_backlight_get_brightness(dell_backlight_dev);
+
+ return 0;
+}
+
+/* --------------------------------------------------------------------------
+ * sysfs
+ * -------------------------------------------------------------------------- */
+
+/* show */
+static ssize_t show_bl_drive_mode(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ char *mode = "unknown";
+
+ switch(backlight_drive_mode) {
+ case BACKLIGHT_DRIVE_BOTH:
+ mode = "BACKLIGHT_DRIVE_BOTH";
+ break;
+ case BACKLIGHT_DRIVE_CURRENT:
+ mode = "BACKLIGHT_DRIVE_CURRENT";
+ break;
+ case BACKLIGHT_DRIVE_BATTERY:
+ mode = "BACKLIGHT_DRIVE_BATTERY";
+ break;
+ case BACKLIGHT_DRIVE_AC:
+ mode = "BACKLIGHT_DRIVE_AC";
+ break;
+ }
+
+ return snprintf(buf, PAGE_SIZE, "%s\n", mode);
+}
+
+static ssize_t show_bl_drive_mode_list(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ int len = 0;
+
+ len = snprintf(buf, PAGE_SIZE, "%d:BACKLIGHT_DRIVE_BOTH\n", BACKLIGHT_DRIVE_BOTH);
+ len += snprintf(buf + len, PAGE_SIZE - len, "%d:BACKLIGHT_DRIVE_CURRENT\n", BACKLIGHT_DRIVE_CURRENT);
+ len += snprintf(buf + len, PAGE_SIZE - len, "%d:BACKLIGHT_DRIVE_BATTERY\n", BACKLIGHT_DRIVE_BATTERY);
+ len += snprintf(buf + len, PAGE_SIZE - len, "%d:BACKLIGHT_DRIVE_AC\n", BACKLIGHT_DRIVE_AC);
+
+ return len;
+}
+
+static ssize_t show_cmdio_port(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ return snprintf(buf, PAGE_SIZE, "0x%04x\n", smi_params.cmdio_port);
+}
+
+static ssize_t show_cmdio_code(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ return snprintf(buf, PAGE_SIZE, "0x%02x\n", smi_params.cmdio_code);
+}
+
+static ssize_t show_bl_location(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ return snprintf(buf, PAGE_SIZE, "0x%04x\n", smi_params.backlight_location);
+}
+
+static ssize_t show_bl_battery_val(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ return snprintf(buf, PAGE_SIZE, "%d\n",
+ brightness_vals[BRIGHTNESS_BATTERY]);
+}
+
+static ssize_t show_bl_ac_val(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ return snprintf(buf, PAGE_SIZE, "%d\n",
+ brightness_vals[BRIGHTNESS_AC]);
+}
+
+static ssize_t show_bl_min_val(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ return snprintf(buf, PAGE_SIZE, "%d\n",
+ brightness_min_value);
+}
+
+static ssize_t show_bl_max_val(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ return snprintf(buf, PAGE_SIZE, "%d\n",
+ dell_backlight_dev->props.max_brightness);
+}
+
+/* store */
+static ssize_t store_bl_drive_mode(struct device *dev,
+ struct device_attribute *attr, const char *buf, size_t count)
+{
+ char *endp;
+ int mode = simple_strtoul(buf, &endp, 0);
+
+ switch(mode) {
+ case BACKLIGHT_DRIVE_BOTH:
+ case BACKLIGHT_DRIVE_BATTERY:
+ case BACKLIGHT_DRIVE_AC:
+ break;
+ case BACKLIGHT_DRIVE_CURRENT:
+ default:
+ return -ENXIO;
+ }
+
+ mutex_lock(&dell_backlight_dev->update_lock);
+ backlight_drive_mode = mode;
+ mutex_unlock(&dell_backlight_dev->update_lock);
+
+ return count;
+}
+
+static ssize_t store_cmdio_port(struct device *dev,
+ struct device_attribute *attr, const char *buf, size_t count)
+{
+ char *endp;
+ int port = simple_strtoul(buf, &endp, 0);
+
+ if (port <= 0 || port >= 0xffff)
+ return -ENXIO;
+
+ mutex_lock(&smi_params.lock);
+ smi_params.cmdio_port = port;
+ mutex_unlock(&smi_params.lock);
+
+ return count;
+}
+
+static ssize_t store_cmdio_code(struct device *dev,
+ struct device_attribute *attr, const char *buf, size_t count)
+{
+ char *endp;
+ int code = simple_strtoul(buf, &endp, 0);
+
+ if (code <= 0 || code >= 0xff)
+ return -ENXIO;
+
+ mutex_lock(&smi_params.lock);
+ smi_params.cmdio_code = code;
+ mutex_unlock(&smi_params.lock);
+
+ return count;
+}
+
+static ssize_t store_bl_location(struct device *dev,
+ struct device_attribute *attr, const char *buf, size_t count)
+{
+ char *endp;
+ int location = simple_strtoul(buf, &endp, 0);
+
+ if (location <= 0 || location >= 0xffff)
+ return -ENXIO;
+
+ mutex_lock(&dell_backlight_dev->update_lock);
+ smi_params.backlight_location = location;
+ mutex_unlock(&dell_backlight_dev->update_lock);
+
+ return count;
+}
+
+static ssize_t store_bl_battery_val(struct device *dev,
+ struct device_attribute *attr, const char *buf, size_t count)
+{
+ char *endp;
+ int level = simple_strtoul(buf, &endp, 0);
+
+ if (level < brightness_min_value ||
+ level > dell_backlight_dev->props.max_brightness)
+ return -ENXIO;
+
+ mutex_lock(&dell_backlight_dev->update_lock);
+ brightness_vals[BRIGHTNESS_BATTERY] = level;
+ write_brightness(SMI_SELECT_BATTERY);
+ update_from_brightness_vals();
+ mutex_unlock(&dell_backlight_dev->update_lock);
+
+ return count;
+}
+
+static ssize_t store_bl_ac_val(struct device *dev,
+ struct device_attribute *attr, const char *buf, size_t count)
+{
+ char *endp;
+ int level = simple_strtoul(buf, &endp, 0);
+
+ if (level < brightness_min_value ||
+ level > dell_backlight_dev->props.max_brightness)
+ return -ENXIO;
+
+ mutex_lock(&dell_backlight_dev->update_lock);
+ brightness_vals[BRIGHTNESS_AC] = level;
+ write_brightness(SMI_SELECT_AC);
+ if (backlight_drive_mode == BACKLIGHT_DRIVE_BOTH) {
+ /* update_from_brightness_vals forces level to battery mode */
+ brightness_vals[BRIGHTNESS_BATTERY] = level;
+ }
+ update_from_brightness_vals();
+ mutex_unlock(&dell_backlight_dev->update_lock);
+
+ return count;
+}
+
+/* static */
+#define DELL_DEVICE_ATTR(_name, _mode, _show, _store) \
+ struct device_attribute dev_attr_##_name = { \
+ .attr = { \
+ .name = __stringify(_name), \
+ .mode = _mode \
+ }, \
+ .show = _show, \
+ .store = _store \
+ }
+
+static DELL_DEVICE_ATTR(backlight_drive_mode, 0666, show_bl_drive_mode, store_bl_drive_mode);
+static DELL_DEVICE_ATTR(backlight_drive_mode_list, 0444, show_bl_drive_mode_list, NULL);
+static DELL_DEVICE_ATTR(cmdio_port, 0600, show_cmdio_port, store_cmdio_port);
+static DELL_DEVICE_ATTR(cmdio_code, 0600, show_cmdio_code, store_cmdio_code);
+static DELL_DEVICE_ATTR(backlight_location, 0600, show_bl_location, store_bl_location);
+static DELL_DEVICE_ATTR(backlight_battery_val, 0666, show_bl_battery_val, store_bl_battery_val);
+static DELL_DEVICE_ATTR(backlight_ac_val, 0666, show_bl_ac_val, store_bl_ac_val);
+static DELL_DEVICE_ATTR(backlight_min_val, 0444, show_bl_min_val, NULL);
+static DELL_DEVICE_ATTR(backlight_max_val, 0444, show_bl_max_val, NULL);
+
+static struct attribute *dell_laptop_attrs[] = {
+ &dev_attr_backlight_drive_mode.attr,
+ &dev_attr_backlight_drive_mode_list.attr,
+ &dev_attr_cmdio_port.attr,
+ &dev_attr_cmdio_code.attr,
+ &dev_attr_backlight_location.attr,
+ &dev_attr_backlight_battery_val.attr,
+ &dev_attr_backlight_ac_val.attr,
+ &dev_attr_backlight_min_val.attr,
+ &dev_attr_backlight_max_val.attr,
+ NULL
+};
+
+static struct attribute_group dell_laptop_attr_group = {
+ .attrs = dell_laptop_attrs
+};
+
+/* --------------------------------------------------------------------------
+ * init / cleanup
+ * -------------------------------------------------------------------------- */
+
+static int __init dell_laptop_init(void)
+{
+ int error;
+
+ error = platform_driver_register(&dell_driver);
+ if (error)
+ return error;
+
+ dell_platform_dev = platform_device_alloc(DRIVER_NAME, -1);
+ if (!dell_platform_dev) {
+ error = -ENOMEM;
+ goto unregister_platform;
+ }
+
+ error = platform_device_add(dell_platform_dev);
+ if (error)
+ goto put_platform;
+
+ /* 32-bit address space */
+ dell_platform_dev->dev.coherent_dma_mask = DMA_32BIT_MASK;
+ dell_platform_dev->dev.dma_mask = &dell_backlight_dev->dev.coherent_dma_mask;
+
+ /* init smi mutex */
+ mutex_init(&smi_params.lock);
+
+ probe_smi_params();
+
+ /* allocate smi buffer */
+ smi_if = dma_alloc_coherent(&dell_platform_dev->dev,
+ SMI_IF_SIZE, &smi_handle, GFP_KERNEL);
+ if (!smi_if) {
+ error = -ENOMEM;
+ goto put_platform;
+ }
+
+ error = dell_backlight_init(&dell_platform_dev->dev);
+ if (error)
+ goto fail_backlight;
+
+ error = sysfs_create_group(&dell_platform_dev->dev.kobj, &dell_laptop_attr_group);
+ if (error) {
+ error = -ENODEV;
+ goto fail_sysfs;
+
+ }
+
+ printk(KERN_INFO DRV_PFX "%s (ver: %s) loaded\n",DRIVER_NAME,DRIVER_VERSION);
+
+ return 0;
+
+
+fail_sysfs:
+ /* */
+fail_backlight:
+ /* */
+put_platform:
+ platform_device_put(dell_platform_dev);
+unregister_platform:
+ platform_driver_unregister(&dell_driver);
+
+ return error;
+}
+
+static void __exit dell_laptop_exit(void)
+{
+ backlight_device_unregister(dell_backlight_dev);
+
+ dma_free_coherent(&dell_platform_dev->dev,
+ SMI_IF_SIZE, smi_if, smi_handle);
+ smi_if = 0;
+ smi_handle = 0;
+
+ sysfs_remove_group(&dell_platform_dev->dev.kobj, &dell_laptop_attr_group);
+
+ platform_device_unregister(dell_platform_dev);
+ platform_driver_unregister(&dell_driver);
+
+ printk(KERN_INFO DRV_PFX "%s (ver: %s) unloaded\n",DRIVER_NAME,DRIVER_VERSION);
+}
+
+module_init(dell_laptop_init);
+module_exit(dell_laptop_exit);
+
--- linux-2.6.23.1/drivers/misc/Kconfig 2007-10-12 18:43:44.000000000 +0200
+++ b/drivers/misc/Kconfig 2007-10-28 15:45:41.000000000 +0100
@@ -130,6 +130,21 @@ config MSI_LAPTOP
If you have an MSI S270 laptop, say Y or M here.
+config DELL_LAPTOP
+ tristate "Dell Laptop Extras (EXPERIMENTAL)"
+ depends on X86
+ depends on EXPERIMENTAL
+ depends on BACKLIGHT_CLASS_DEVICE
+ ---help---
+ This driver implements LCD backlight control for Dell laptops. BEFORE
+ using this driver, please fill in your laptop model parameters as described
+ in dell-laptop.txt. Using this driver without doing this operation
+ may have UNPREDICTABLE effects on your laptop. You have been warned!
+
+ Just read <file:Documentation/dell-laptop.txt> first.
+
+ If you have a Dell laptop, say Y or M here.
+
config SONY_LAPTOP
tristate "Sony Laptop Extras"
depends on X86 && ACPI
On Sun, Oct 28, 2007 at 05:12:37PM +0100, [email protected] wrote:
> Hello,
> this driver implements backlight control on Dell laptops
> which use SMI for changing brightness levels.
>
> The driver is INCOMPLETE since it is unable to probe some required
> parameters
> in order to perform backlight control. Such parameters are found in a Dell
> proprietary DMI table which should be parsed. For now external tools may be
> used to find these parameters by hand. So if you intend to try this out,
> FIRST write your laptop model parameters correctly inside the source code
> as explained in Documentation/dell-laptop.txt.
>
> Parts of this driver may also be used to provide additional functionalities
> similarly to the drivers/misc/*-laptop.c drivers.
Why is this better done in the kernel rather than in userspace with
libsmbios as you've noted?
--
Matt Domsch
Linux Technology Strategist, Dell Office of the CTO
linux.dell.com & http://www.dell.com/linux
Matt Domsch wrote:
> On Sun, Oct 28, 2007 at 05:12:37PM +0100, [email protected] wrote:
>> Hello,
>> this driver implements backlight control on Dell laptops
>> which use SMI for changing brightness levels.
>>
>> The driver is INCOMPLETE since it is unable to probe some required
>> parameters
>> in order to perform backlight control. Such parameters are found in a Dell
>> proprietary DMI table which should be parsed. For now external tools may be
>> used to find these parameters by hand. So if you intend to try this out,
>> FIRST write your laptop model parameters correctly inside the source code
>> as explained in Documentation/dell-laptop.txt.
>>
>> Parts of this driver may also be used to provide additional functionalities
>> similarly to the drivers/misc/*-laptop.c drivers.
>
> Why is this better done in the kernel rather than in userspace with
> libsmbios as you've noted?
>
I had to do a kernelspace driver for controlling the backlight. This
was part of a college project assignment. In order for it to be valid
for an operating system course, it had to be in kernelspace (not
Unix programming) :).
As i mentioned that can be done in userspace and it IS sensible to do
so. I know that the code which was already written for Dell implied
a userspace approach, but i simply had no choice.
I also don't expect this driver to become mainstream, but since i have
written it, other people might want to have a look at it.
Finally i really don't think there's any sensible way of implementing
Linux LCD Backlight Abstraction relying on a userspace application.
That would mean the kernel calling userspace code to change the
brightness, then this latter code would again call the kernel to trigger
a SMI and so on. That's just not a good design. I think a userspace
solution implies choosing NOT to implement the LCD Abstraction. Causing
Dell laptops to be treated differently from other machines (as they are
not compliant with Linux's own interface).
jacopo
On Sun, Oct 28, 2007 at 07:06:23PM +0100, [email protected] wrote:
> Matt Domsch wrote:
> >On Sun, Oct 28, 2007 at 05:12:37PM +0100, [email protected] wrote:
> >>Hello,
> >>this driver implements backlight control on Dell laptops
> >>which use SMI for changing brightness levels.
> >>
> >>The driver is INCOMPLETE since it is unable to probe some required
> >>parameters
> >>in order to perform backlight control. Such parameters are found in a Dell
> >>proprietary DMI table which should be parsed. For now external tools may
> >>be
> >>used to find these parameters by hand. So if you intend to try this out,
> >>FIRST write your laptop model parameters correctly inside the source code
> >>as explained in Documentation/dell-laptop.txt.
> >>
> >>Parts of this driver may also be used to provide additional
> >>functionalities
> >>similarly to the drivers/misc/*-laptop.c drivers.
> >
> >Why is this better done in the kernel rather than in userspace with
> >libsmbios as you've noted?
> >
>
> I had to do a kernelspace driver for controlling the backlight. This
> was part of a college project assignment. In order for it to be valid
> for an operating system course, it had to be in kernelspace (not
> Unix programming) :).
>
> As i mentioned that can be done in userspace and it IS sensible to do
> so. I know that the code which was already written for Dell implied
> a userspace approach, but i simply had no choice.
>
> I also don't expect this driver to become mainstream, but since i have
> written it, other people might want to have a look at it.
OK, that's fair.
> Finally i really don't think there's any sensible way of implementing
> Linux LCD Backlight Abstraction relying on a userspace application.
> That would mean the kernel calling userspace code to change the
> brightness, then this latter code would again call the kernel to trigger
> a SMI and so on. That's just not a good design. I think a userspace
> solution implies choosing NOT to implement the LCD Abstraction. Causing
> Dell laptops to be treated differently from other machines (as they are
> not compliant with Linux's own interface).
I've had this discussion on lkml before. Short story is, until Dell
laptops implement the ACPI methods that the backlight API expects, the
only sane way to do it is to let libsmbios handle it. Moving the
fairly large and complex libsmbios into the kernel isn't a good idea
(imho).
--
Matt Domsch
Linux Technology Strategist, Dell Office of the CTO
linux.dell.com & http://www.dell.com/linux
Fixed style.
jacopo
--- linux-2.6.23.1/Documentation/dell-laptop.txt 1970-01-01 01:00:00.000000000 +0100
+++ b/Documentation/dell-laptop.txt 2007-10-28 23:25:26.000000000 +0100
@@ -0,0 +1,107 @@
+This driver is EXPERIMENTAL, use it at YOUR OWN RISK.
+
+BEFORE TRYING THIS DRIVER OUT:
+You MUST FILL IN your laptop parameters in the source code. This
+driver is not capable of probing these parameters on its own.
+
+The parameters involved are:
+- IO Port address
+- IO command code
+- Location
+
+These parameters depend (hopefully) on the model of your laptop.
+Such information is found in a private Dell DMI table. You may
+use dmidecode or libsmbios' dumpCmos
+(http://linux.dell.com/libsmbios/download/libsmbios/). The
+latter is best since it DECODES COMPLETELY Dell's tokens.
+
+******************************************************* WITH LIBSMBIOS
+root@here:~# dumpCmos | grep 0x007d
+and you will get a line like the following...
+DMI type 0xda Handle 0xda00 CmdIO Port 0x00b2 CmdIO Code 0x0d \
+ Type 0x007d Location 0x0000 value 0000
+
+open dell-laptop.c and write the parameters accordingly under
+the probe_smi_params() function
+
+static int probe_smi_params(void)
+{
+ /*
+ * these should be probed by parsing Dell's CMOS table (type 0xda)
+ */
+ smi_params.cmdio_port = 0x00b2; /* dumpCmos CmdIO Port */
+ smi_params.cmdio_code = 0x0d; /* dumpCmos CmdIO Code */
+ smi_params.backlight_location = 0; /* dumpCmos Location */
+ smi_params.backlight_value = 0; /* dumpCmos Value (unused) */
+
+ return 0;
+}
+**********************************************************************
+
+******************************************************* WITH DMIDECODE
+(this is HAND parsing!!)
+dmidecode & look for table type 218
+
+Handle 0xDA00, DMI type 218, 125 bytes
+OEM-specific Type
+ Header and Data:
+ DA 7D 00 DA B2 00 0D 5F 0F 37 40 7D 00 00 00 00
+ 00 7E 00 02 00 00 00 40 00 04 00 01 00 41 00 04
+ 00 00 00 90 00 05 00 00 00 91 00 05 00 01 00 92
+ 00 05 00 02 00 45 01 45 01 01 00 44 01 44 01 00
+ 00 00 80 00 80 01 00 00 A0 00 A0 01 00 05 80 05
+ 80 01 00 76 01 76 01 01 00 75 01 75 01 01 00 01
+ F0 01 F0 00 00 02 F0 02 F0 00 00 03 F0 03 F0 00
+ 00 04 F0 04 F0 00 00 FF FF 00 00 00 00
+
+now you have:
+1 byte DA (table type)
+1 byte 7D (table size)
+2 bytes 00 DA (handle)
+2 bytes B2 00 (cmdio port address (swapped) )
+1 byte 0D (cmdio code)
+4 bytes 5F 0F 37 40 (supported commands ?)
+
+after that you have triplets terminated by FF FF 00 00 00 00
+in the form (type, location, value)
+
+type | loc | val
+7D 00|00 00|00 00
+7E 00|02 00|00 00
+40 00|04 00|01 00
+41 00|04 00|00 00
+90 00|05 00|00 00
+91 00|05 00|01 00
+92 00|05 00|02 00
+45 01|45 01|01 00
+44 01|44 01|00 00
+00 80|00 80|01 00
+00 A0|00 A0|01 00
+05 80|05 80|01 00
+76 01|76 01|01 00
+75 01|75 01|01 00
+01 F0|01 F0|00 00
+02 F0|02 F0|00 00
+03 F0|03 F0|00 00
+04 F0|04 F0|00 00
+end
+FF FF|00 00|00 00
+
+you can read the Location field in type 0x007d (swapped 7D 00)
+
+then modify dell-laptop.c accordingly (remember to swap the lsb
+with the msb in the port address also!)
+
+static int probe_smi_params(void)
+{
+ /*
+ * these should be probed by parsing Dell's CMOS table (type 0xda)
+ */
+ smi_params.cmdio_port = 0x00b2; /* dumpCmos CmdIO Port */
+ smi_params.cmdio_code = 0x0d; /* dumpCmos CmdIO Code */
+ smi_params.backlight_location = 0; /* dumpCmos Location */
+ smi_params.backlight_value = 0; /* dumpCmos Value (unused) */
+
+ return 0;
+}
+**********************************************************************
--- linux-2.6.23.1/drivers/misc/Makefile 2007-10-12 18:43:44.000000000 +0200
+++ b/drivers/misc/Makefile 2007-10-28 16:42:12.000000000 +0100
@@ -15,3 +15,4 @@ obj-$(CONFIG_SGI_IOC4) += ioc4.o
obj-$(CONFIG_SONY_LAPTOP) += sony-laptop.o
obj-$(CONFIG_THINKPAD_ACPI) += thinkpad_acpi.o
obj-$(CONFIG_EEPROM_93CX6) += eeprom_93cx6.o
+obj-$(CONFIG_DELL_LAPTOP) += dell-laptop.o
--- linux-2.6.23.1/drivers/misc/dell-laptop.h 1970-01-01 01:00:00.000000000 +0100
+++ b/drivers/misc/dell-laptop.h 2007-10-28 21:57:21.000000000 +0100
@@ -0,0 +1,117 @@
+/*
+ * dell-laptop.h - Dell laptop extras
+ *
+ *
+ * Copyright (C) 2007 Jacopo Antonello <[email protected]>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+ * 02110-1301, USA.
+ */
+
+#ifndef _DELL_LAPTOP_H_
+#define _DELL_LAPTOP_H_
+
+#include <linux/device.h>
+#include <linux/sysfs.h>
+#include <linux/types.h>
+
+#define SMI_CMD_MAGIC 0x534D4931 /* "SMI1" */
+#define SMI_CMD_ECX 0x42534931 /* "BSI1" */
+
+#define SMI_CMD_SIZE sizeof(struct smi_cmd)
+#define SMI_BUF_SIZE sizeof(struct smi_cmd_buffer)
+#define SMI_IF_SIZE (SMI_CMD_SIZE + SMI_BUF_SIZE)
+
+#define SMI_CLASS_READ_SETTING 0
+#define SMI_CLASS_WRITE_SETTING 1
+
+#define SMI_SELECT_BATTERY 1
+#define SMI_SELECT_AC 2
+
+#define BRIGHTNESS_BATTERY (SMI_SELECT_BATTERY - 1)
+#define BRIGHTNESS_AC (SMI_SELECT_AC - 1)
+
+#define DELL_TABLE_DA 0xda
+#define DELL_CALLIF_ID_BACKLIGHT 0x007d
+
+#define DRIVER_NAME "dell-laptop"
+#define DRIVER_DESCRIPTION "Dell laptop extras"
+#define DRV_PFX "dell-laptop: "
+
+struct smi_cmd {
+ __u32 magic;
+ __u32 ebx;
+ __u32 ecx;
+ __u16 command_address;
+ __u8 command_code;
+ __u8 reserved;
+ /* __u8 command_buffer[1]; */
+} __attribute__ ((packed));
+
+struct smi_cmd_buffer
+{
+ __u16 smi_class;
+ __u16 smi_select;
+
+ __u32 cbARG1;
+ __u32 cbARG2;
+ __u32 cbARG3;
+ __u32 cbARG4;
+
+ __s32 cbRES1;
+ __s32 cbRES2;
+ __s32 cbRES3;
+ __s32 cbRES4;
+} __attribute__ ((packed));
+
+struct smi_params_t {
+ /* serialize smi calls */
+ struct mutex lock;
+
+ u16 cmdio_port;
+ u8 cmdio_code;
+ u32 supported_cmds;
+
+ u16 backlight_location;
+ u16 backlight_value;
+};
+
+enum backlight_drive_mode {
+ BACKLIGHT_DRIVE_BOTH,
+ BACKLIGHT_DRIVE_CURRENT,
+ BACKLIGHT_DRIVE_BATTERY,
+ BACKLIGHT_DRIVE_AC
+};
+
+static struct platform_driver dell_driver = {
+ .driver = {
+ .name = DRIVER_NAME,
+ .owner = THIS_MODULE,
+ }
+};
+
+static struct backlight_device *dell_backlight_dev;
+static struct platform_device *dell_platform_dev;
+
+static u8 *smi_if;
+static dma_addr_t smi_handle;
+
+static struct smi_params_t smi_params;
+
+static enum backlight_drive_mode backlight_drive_mode;
+static u32 brightness_vals[2];
+static u32 brightness_min_value;
+
+#endif
--- linux-2.6.23.1/drivers/misc/dell-laptop.c 1970-01-01 01:00:00.000000000 +0100
+++ b/drivers/misc/dell-laptop.c 2007-10-28 22:17:09.000000000 +0100
@@ -0,0 +1,683 @@
+/*
+ * dell-laptop.c - Dell laptop extras
+ *
+ * This driver implements only backlight control for now.
+ * This driver assumes that you are not using bios password
+ * protection and does not work if it is enabled.
+ *
+ * This driver is EXPERIMENTAL and it is not yet complete. In
+ * particular it lacks proper probing for the hardware
+ * it is meant to control.
+ *
+ * WARNING: you MUST fill in your laptop CMOS parameters, by
+ * modifying the default values found in probe_smi_params().
+ * Failing to do so could cause unpredictable effects on your
+ * laptop. In order to do this you may use the dumpCmos utility
+ * found in libsmbios
+ * (http://linux.dell.com/libsmbios/download/libsmbios/)
+ *
+ * Parts of this driver were inspired by dcdbas.c and libsmbios
+ * (http://linux.dell.com/libsmbios/download/libsmbios/)
+ *
+ * Copyright (C) 2007 Jacopo Antonello <[email protected]>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+ * 02110-1301, USA.
+ */
+
+#define DRIVER_VERSION "0.1"
+
+/*
+ * Changelog:
+ * 2007-12-22 0.01 initial release
+ * support for backlight on Dell M70 laptops
+ * TODO fix framebuffer support
+ * TODO add cmos token lookup
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/dma-mapping.h>
+#include <linux/mutex.h>
+#include <linux/sched.h>
+#include <linux/backlight.h>
+
+#include "dell-laptop.h"
+
+MODULE_DESCRIPTION(DRIVER_DESCRIPTION " (version " DRIVER_VERSION ")");
+MODULE_VERSION(DRIVER_VERSION);
+MODULE_AUTHOR("jacopo antonello <jack at antonello.org>");
+MODULE_LICENSE("GPL");
+
+/* --------------------------------------------------------------------------
+ * smi
+ * -------------------------------------------------------------------------- */
+
+static int probe_smi_params(void)
+{
+ /*
+ * these should be probed by parsing Dell's CMOS table (dmi type 0xda)
+ */
+ smi_params.cmdio_port = 0x00b2; /* libsmbios' dumpCmos CmdIO Port */
+ smi_params.cmdio_code = 0x0d; /* libsmbios' dumpCmos CmdIO Code */
+ smi_params.backlight_location = 0; /* set to dumpCmos Location */
+ smi_params.backlight_value = 0; /* set to dumpCmos Value (unused) */
+
+ return 0;
+}
+
+static int trigger_smi(u16 ioport, u8 iocode, struct smi_cmd_buffer *parms)
+{
+ struct smi_cmd *cmd = (struct smi_cmd *)smi_if;
+ struct smi_cmd_buffer *buf = (struct smi_cmd_buffer *)
+ (smi_if + SMI_CMD_SIZE);
+ cpumask_t old_mask;
+ int ret = 0;
+
+ mutex_lock(&smi_params.lock);
+
+ cmd->magic = SMI_CMD_MAGIC;
+ cmd->ebx = (u32)virt_to_phys(buf);
+ cmd->ecx = SMI_CMD_ECX;
+ cmd->command_address = ioport; /* libsmbios' dumpCmos CmdIO Port */
+ cmd->command_code = iocode; /* libsmbios' dumpCmos CmdIO Code */
+ cmd->reserved = 0;
+
+ buf->smi_class = parms->smi_class; /* 0 read, 1 write */
+ buf->smi_select = parms->smi_select; /* 1 battery mode, 2 ac mode */
+
+ buf->cbARG1 = parms->cbARG1; /* set to dumpCmos Location */
+ buf->cbARG2 = parms->cbARG2;
+ buf->cbARG3 = parms->cbARG3;
+ buf->cbARG4 = parms->cbARG4;
+
+ buf->cbRES1 = parms->cbRES1; /* set to -1 to tell errors */
+ buf->cbRES2 = parms->cbRES2;
+ buf->cbRES3 = parms->cbRES3;
+ buf->cbRES4 = parms->cbRES4;
+
+ /* dcdbas.c */
+ old_mask = current->cpus_allowed;
+ set_cpus_allowed(current, cpumask_of_cpu(0));
+ if (smp_processor_id() != 0) {
+ dev_dbg(&dell_backlight_dev->dev, "%s: failed to get CPU 0\n",
+ __FUNCTION__);
+ ret = -EBUSY;
+ goto out;
+ }
+
+ asm volatile (
+ "outb %b0,%w1"
+ : /* no output args */
+ : "a" (cmd->command_code),
+ "d" (cmd->command_address),
+ "b" (cmd->ebx),
+ "c" (cmd->ecx)
+ : "memory");
+
+ switch (buf->cbRES1) {
+ case -6: /* output buffer not large enough */
+ case -5: /* output buffer format error */
+ case -3: /* unhandled smi call */
+ case -2: /* unsupported smi call */
+ case -1: /* bios returned error for smi call */
+ ret = -EBUSY;
+ printk(KERN_WARNING DRV_PFX "SMI failed\n");
+ goto out;
+ }
+
+ /* copy back results */
+ parms->smi_class = buf->smi_class;
+ parms->smi_select = buf->smi_select;
+
+ parms->cbARG1 = buf->cbARG1;
+ parms->cbARG2 = buf->cbARG2;
+ parms->cbARG3 = buf->cbARG3;
+ parms->cbARG4 = buf->cbARG4;
+
+ parms->cbRES1 = buf->cbRES1;
+ parms->cbRES2 = buf->cbRES2;
+ parms->cbRES3 = buf->cbRES3;
+ parms->cbRES4 = buf->cbRES4;
+
+out:
+ set_cpus_allowed(current, old_mask);
+
+ mutex_unlock(&smi_params.lock);
+
+ return ret;
+}
+
+/* --------------------------------------------------------------------------
+ * brightness
+ * -------------------------------------------------------------------------- */
+
+/* use read_brightness(SMI_SELECT_*) */
+static void read_brightness(int select)
+{
+ struct smi_cmd_buffer buf = {
+ .smi_class = SMI_CLASS_READ_SETTING,
+ .smi_select = select,
+
+ .cbARG1 = smi_params.backlight_location,
+ .cbARG2 = 0,
+ .cbARG3 = 0,
+ .cbARG4 = 0,
+
+ .cbRES1 = -1,
+ .cbRES2 = 0,
+ .cbRES3 = 0,
+ .cbRES4 = 0
+ };
+
+ if (trigger_smi(smi_params.cmdio_port, smi_params.cmdio_code, &buf)) {
+ printk(KERN_ERR DRV_PFX "unable to read brightness levels\n");
+ return;
+ }
+
+ brightness_vals[select - 1] = buf.cbRES2;
+ printk(KERN_DEBUG DRV_PFX " brightness_vals[ %d ]: %d\n", select - 1,
+ brightness_vals[select - 1]);
+ brightness_min_value = buf.cbRES3;
+ printk(KERN_DEBUG DRV_PFX " brightness_min_value: %d\n",
+ brightness_min_value);
+ dell_backlight_dev->props.max_brightness = buf.cbRES4;
+ printk(KERN_DEBUG DRV_PFX " props.max_brightness: %d\n",
+ dell_backlight_dev->props.max_brightness);
+}
+
+/* use write_brightness(SMI_SELECT_*) */
+static void write_brightness(int select)
+{
+ struct smi_cmd_buffer buf = {
+ .smi_class = SMI_CLASS_WRITE_SETTING,
+ .smi_select = select,
+
+ .cbARG1 = smi_params.backlight_location,
+ .cbARG2 = brightness_vals[select - 1],
+ .cbARG3 = 0,
+ .cbARG4 = 0,
+
+ .cbRES1 = -1,
+ .cbRES2 = 0,
+ .cbRES3 = 0,
+ .cbRES4 = 0
+ };
+
+ if (trigger_smi(smi_params.cmdio_port, smi_params.cmdio_code, &buf)) {
+ printk(KERN_ERR DRV_PFX "unable to write brightness\n");
+ return;
+ }
+
+ if (buf.cbRES2 != brightness_vals[select - 1])
+ printk(KERN_ERR DRV_PFX "brightness value unchanged\n");
+
+ brightness_vals[select - 1] = buf.cbRES2;
+ printk(KERN_DEBUG DRV_PFX " brightness_vals[ %d ]: %d\n", select - 1,
+ brightness_vals[select - 1]);
+}
+
+static int dell_backlight_update_status(struct backlight_device *dev)
+{
+ dev->props.brightness = dev->props.brightness < brightness_min_value ?
+ brightness_min_value :
+ dev->props.brightness > dev->props.max_brightness ?
+ dev->props.max_brightness : dev->props.brightness;
+
+ switch (backlight_drive_mode) {
+ case BACKLIGHT_DRIVE_BOTH:
+ brightness_vals[BRIGHTNESS_BATTERY] = dev->props.brightness;
+ brightness_vals[BRIGHTNESS_AC] = dev->props.brightness;
+ write_brightness(SMI_SELECT_BATTERY);
+ write_brightness(SMI_SELECT_AC);
+ break;
+ case BACKLIGHT_DRIVE_AC:
+ brightness_vals[BRIGHTNESS_AC] = dev->props.brightness;
+ write_brightness(SMI_SELECT_AC);
+ break;
+ case BACKLIGHT_DRIVE_BATTERY:
+ brightness_vals[BRIGHTNESS_BATTERY] = dev->props.brightness;
+ write_brightness(SMI_SELECT_BATTERY);
+ break;
+ case BACKLIGHT_DRIVE_CURRENT:
+ printk(KERN_ERR DRV_PFX
+ "BACKLIGHT_DRIVER_CURRENT unimplemented\n");
+ default:
+ printk(KERN_ERR DRV_PFX "unknown backlight_drive_mode\n");
+ }
+
+ return dev->props.brightness;
+}
+
+static void update_from_brightness_vals(void)
+{
+ switch (backlight_drive_mode) {
+ case BACKLIGHT_DRIVE_BOTH:
+ dell_backlight_dev->props.brightness =
+ brightness_vals[BRIGHTNESS_BATTERY];
+ if (brightness_vals[BRIGHTNESS_AC] !=
+ brightness_vals[BRIGHTNESS_BATTERY]) {
+ brightness_vals[BRIGHTNESS_AC] =
+ brightness_vals[BRIGHTNESS_BATTERY];
+ /* force ac to the same value */
+ write_brightness(SMI_SELECT_AC);
+ }
+ break;
+ case BACKLIGHT_DRIVE_AC:
+ dell_backlight_dev->props.brightness =
+ brightness_vals[BRIGHTNESS_AC];
+ break;
+ case BACKLIGHT_DRIVE_BATTERY:
+ dell_backlight_dev->props.brightness =
+ brightness_vals[BRIGHTNESS_BATTERY];
+ break;
+ case BACKLIGHT_DRIVE_CURRENT:
+ printk(KERN_ERR DRV_PFX
+ "BACKLIGHT_DRIVER_CURRENT unimplemented\n");
+ default:
+ printk(KERN_ERR DRV_PFX "unknown backlight_drive_mode\n");
+ }
+}
+
+static int dell_backlight_get_brightness(struct backlight_device *dev)
+{
+ /* is locking needed? */
+ mutex_lock(&dell_backlight_dev->update_lock);
+
+ read_brightness(SMI_SELECT_BATTERY);
+ read_brightness(SMI_SELECT_AC);
+
+ update_from_brightness_vals();
+
+ mutex_unlock(&dell_backlight_dev->update_lock);
+
+ return dev->props.brightness;
+}
+
+static struct backlight_ops dell_backlight_ops = {
+ .update_status = dell_backlight_update_status,
+ .get_brightness = dell_backlight_get_brightness
+};
+
+static int dell_backlight_init(struct device *dev)
+{
+ dell_backlight_dev = backlight_device_register(
+ "dell-laptop",
+ NULL,
+ NULL,
+ &dell_backlight_ops);
+
+ if (IS_ERR(dell_backlight_dev)) {
+ dell_backlight_dev = NULL;
+ return PTR_ERR(dell_backlight_dev);
+ }
+
+ backlight_drive_mode = BACKLIGHT_DRIVE_AC;
+
+ dell_backlight_get_brightness(dell_backlight_dev);
+
+ return 0;
+}
+
+/* --------------------------------------------------------------------------
+ * sysfs
+ * -------------------------------------------------------------------------- */
+
+/* show */
+static ssize_t show_bl_drive_mode(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ char *mode = "unknown";
+
+ switch (backlight_drive_mode) {
+ case BACKLIGHT_DRIVE_BOTH:
+ mode = "BACKLIGHT_DRIVE_BOTH";
+ break;
+ case BACKLIGHT_DRIVE_CURRENT:
+ mode = "BACKLIGHT_DRIVE_CURRENT";
+ break;
+ case BACKLIGHT_DRIVE_BATTERY:
+ mode = "BACKLIGHT_DRIVE_BATTERY";
+ break;
+ case BACKLIGHT_DRIVE_AC:
+ mode = "BACKLIGHT_DRIVE_AC";
+ break;
+ }
+
+ return snprintf(buf, PAGE_SIZE, "%s\n", mode);
+}
+
+static ssize_t show_bl_drive_mode_list(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ int len = 0;
+
+ len = snprintf(buf, PAGE_SIZE,
+ "%d:BACKLIGHT_DRIVE_BOTH\n",
+ BACKLIGHT_DRIVE_BOTH);
+ len += snprintf(buf + len, PAGE_SIZE - len,
+ "%d:BACKLIGHT_DRIVE_CURRENT\n",
+ BACKLIGHT_DRIVE_CURRENT);
+ len += snprintf(buf + len, PAGE_SIZE - len,
+ "%d:BACKLIGHT_DRIVE_BATTERY\n",
+ BACKLIGHT_DRIVE_BATTERY);
+ len += snprintf(buf + len, PAGE_SIZE - len,
+ "%d:BACKLIGHT_DRIVE_AC\n",
+ BACKLIGHT_DRIVE_AC);
+
+ return len;
+}
+
+static ssize_t show_cmdio_port(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ return snprintf(buf, PAGE_SIZE, "0x%04x\n", smi_params.cmdio_port);
+}
+
+static ssize_t show_cmdio_code(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ return snprintf(buf, PAGE_SIZE, "0x%02x\n", smi_params.cmdio_code);
+}
+
+static ssize_t show_bl_location(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ return snprintf(buf, PAGE_SIZE, "0x%04x\n",
+ smi_params.backlight_location);
+}
+
+static ssize_t show_bl_battery_val(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ return snprintf(buf, PAGE_SIZE, "%d\n",
+ brightness_vals[BRIGHTNESS_BATTERY]);
+}
+
+static ssize_t show_bl_ac_val(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ return snprintf(buf, PAGE_SIZE, "%d\n",
+ brightness_vals[BRIGHTNESS_AC]);
+}
+
+static ssize_t show_bl_min_val(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ return snprintf(buf, PAGE_SIZE, "%d\n",
+ brightness_min_value);
+}
+
+static ssize_t show_bl_max_val(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ return snprintf(buf, PAGE_SIZE, "%d\n",
+ dell_backlight_dev->props.max_brightness);
+}
+
+/* store */
+static ssize_t store_bl_drive_mode(struct device *dev,
+ struct device_attribute *attr, const char *buf, size_t count)
+{
+ char *endp;
+ int mode = simple_strtoul(buf, &endp, 0);
+
+ switch (mode) {
+ case BACKLIGHT_DRIVE_BOTH:
+ case BACKLIGHT_DRIVE_BATTERY:
+ case BACKLIGHT_DRIVE_AC:
+ break;
+ case BACKLIGHT_DRIVE_CURRENT:
+ default:
+ return -ENXIO;
+ }
+
+ mutex_lock(&dell_backlight_dev->update_lock);
+ backlight_drive_mode = mode;
+ mutex_unlock(&dell_backlight_dev->update_lock);
+
+ return count;
+}
+
+static ssize_t store_cmdio_port(struct device *dev,
+ struct device_attribute *attr, const char *buf, size_t count)
+{
+ char *endp;
+ int port = simple_strtoul(buf, &endp, 0);
+
+ if (port <= 0 || port >= 0xffff)
+ return -ENXIO;
+
+ mutex_lock(&smi_params.lock);
+ smi_params.cmdio_port = port;
+ mutex_unlock(&smi_params.lock);
+
+ return count;
+}
+
+static ssize_t store_cmdio_code(struct device *dev,
+ struct device_attribute *attr, const char *buf, size_t count)
+{
+ char *endp;
+ int code = simple_strtoul(buf, &endp, 0);
+
+ if (code <= 0 || code >= 0xff)
+ return -ENXIO;
+
+ mutex_lock(&smi_params.lock);
+ smi_params.cmdio_code = code;
+ mutex_unlock(&smi_params.lock);
+
+ return count;
+}
+
+static ssize_t store_bl_location(struct device *dev,
+ struct device_attribute *attr, const char *buf, size_t count)
+{
+ char *endp;
+ int location = simple_strtoul(buf, &endp, 0);
+
+ if (location <= 0 || location >= 0xffff)
+ return -ENXIO;
+
+ mutex_lock(&dell_backlight_dev->update_lock);
+ smi_params.backlight_location = location;
+ mutex_unlock(&dell_backlight_dev->update_lock);
+
+ return count;
+}
+
+static ssize_t store_bl_battery_val(struct device *dev,
+ struct device_attribute *attr, const char *buf, size_t count)
+{
+ char *endp;
+ int level = simple_strtoul(buf, &endp, 0);
+
+ if (level < brightness_min_value ||
+ level > dell_backlight_dev->props.max_brightness)
+ return -ENXIO;
+
+ mutex_lock(&dell_backlight_dev->update_lock);
+ brightness_vals[BRIGHTNESS_BATTERY] = level;
+ write_brightness(SMI_SELECT_BATTERY);
+ update_from_brightness_vals();
+ mutex_unlock(&dell_backlight_dev->update_lock);
+
+ return count;
+}
+
+static ssize_t store_bl_ac_val(struct device *dev,
+ struct device_attribute *attr, const char *buf, size_t count)
+{
+ char *endp;
+ int level = simple_strtoul(buf, &endp, 0);
+
+ if (level < brightness_min_value ||
+ level > dell_backlight_dev->props.max_brightness)
+ return -ENXIO;
+
+ mutex_lock(&dell_backlight_dev->update_lock);
+ brightness_vals[BRIGHTNESS_AC] = level;
+ write_brightness(SMI_SELECT_AC);
+ if (backlight_drive_mode == BACKLIGHT_DRIVE_BOTH) {
+ /* update_from_brightness_vals forces level to battery mode */
+ brightness_vals[BRIGHTNESS_BATTERY] = level;
+ }
+ update_from_brightness_vals();
+ mutex_unlock(&dell_backlight_dev->update_lock);
+
+ return count;
+}
+
+/* static */
+#define DELL_DEVICE_ATTR(_name, _mode, _show, _store) \
+ struct device_attribute dev_attr_##_name = { \
+ .attr = { \
+ .name = __stringify(_name), \
+ .mode = _mode \
+ }, \
+ .show = _show, \
+ .store = _store \
+ }
+
+static DELL_DEVICE_ATTR(backlight_drive_mode, 0666,
+ show_bl_drive_mode, store_bl_drive_mode);
+static DELL_DEVICE_ATTR(backlight_drive_mode_list, 0444,
+ show_bl_drive_mode_list, NULL);
+static DELL_DEVICE_ATTR(cmdio_port, 0600,
+ show_cmdio_port, store_cmdio_port);
+static DELL_DEVICE_ATTR(cmdio_code, 0600,
+ show_cmdio_code, store_cmdio_code);
+static DELL_DEVICE_ATTR(backlight_location, 0600,
+ show_bl_location, store_bl_location);
+static DELL_DEVICE_ATTR(backlight_battery_val, 0666,
+ show_bl_battery_val, store_bl_battery_val);
+static DELL_DEVICE_ATTR(backlight_ac_val, 0666,
+ show_bl_ac_val, store_bl_ac_val);
+static DELL_DEVICE_ATTR(backlight_min_val, 0444,
+ show_bl_min_val, NULL);
+static DELL_DEVICE_ATTR(backlight_max_val, 0444,
+ show_bl_max_val, NULL);
+
+static struct attribute *dell_laptop_attrs[] = {
+ &dev_attr_backlight_drive_mode.attr,
+ &dev_attr_backlight_drive_mode_list.attr,
+ &dev_attr_cmdio_port.attr,
+ &dev_attr_cmdio_code.attr,
+ &dev_attr_backlight_location.attr,
+ &dev_attr_backlight_battery_val.attr,
+ &dev_attr_backlight_ac_val.attr,
+ &dev_attr_backlight_min_val.attr,
+ &dev_attr_backlight_max_val.attr,
+ NULL
+};
+
+static struct attribute_group dell_laptop_attr_group = {
+ .attrs = dell_laptop_attrs
+};
+
+/* --------------------------------------------------------------------------
+ * init / cleanup
+ * -------------------------------------------------------------------------- */
+
+static int __init dell_laptop_init(void)
+{
+ int error;
+
+ error = platform_driver_register(&dell_driver);
+ if (error)
+ return error;
+
+ dell_platform_dev = platform_device_alloc(DRIVER_NAME, -1);
+ if (!dell_platform_dev) {
+ error = -ENOMEM;
+ goto unregister_platform;
+ }
+
+ error = platform_device_add(dell_platform_dev);
+ if (error)
+ goto put_platform;
+
+ /* 32-bit address space */
+ dell_platform_dev->dev.coherent_dma_mask = DMA_32BIT_MASK;
+ dell_platform_dev->dev.dma_mask =
+ &dell_backlight_dev->dev.coherent_dma_mask;
+
+ /* init smi mutex */
+ mutex_init(&smi_params.lock);
+
+ probe_smi_params();
+
+ /* allocate smi buffer */
+ smi_if = dma_alloc_coherent(&dell_platform_dev->dev,
+ SMI_IF_SIZE, &smi_handle, GFP_KERNEL);
+ if (!smi_if) {
+ error = -ENOMEM;
+ goto put_platform;
+ }
+
+ error = dell_backlight_init(&dell_platform_dev->dev);
+ if (error)
+ goto fail_backlight;
+
+ error = sysfs_create_group(&dell_platform_dev->dev.kobj,
+ &dell_laptop_attr_group);
+ if (error) {
+ error = -ENODEV;
+ goto fail_sysfs;
+
+ }
+
+ printk(KERN_INFO DRV_PFX "%s (ver: %s) loaded\n",
+ DRIVER_NAME, DRIVER_VERSION);
+
+ return 0;
+
+
+fail_sysfs:
+ /* */
+fail_backlight:
+ /* */
+put_platform:
+ platform_device_put(dell_platform_dev);
+unregister_platform:
+ platform_driver_unregister(&dell_driver);
+
+ return error;
+}
+
+static void __exit dell_laptop_exit(void)
+{
+ backlight_device_unregister(dell_backlight_dev);
+
+ dma_free_coherent(&dell_platform_dev->dev,
+ SMI_IF_SIZE, smi_if, smi_handle);
+ smi_if = 0;
+ smi_handle = 0;
+
+ sysfs_remove_group(&dell_platform_dev->dev.kobj,
+ &dell_laptop_attr_group);
+
+ platform_device_unregister(dell_platform_dev);
+ platform_driver_unregister(&dell_driver);
+
+ printk(KERN_INFO DRV_PFX "%s (ver: %s) unloaded\n",
+ DRIVER_NAME, DRIVER_VERSION);
+}
+
+module_init(dell_laptop_init);
+module_exit(dell_laptop_exit);
+
--- linux-2.6.23.1/drivers/misc/Kconfig 2007-10-12 18:43:44.000000000 +0200
+++ b/drivers/misc/Kconfig 2007-10-28 16:42:12.000000000 +0100
@@ -130,6 +130,21 @@ config MSI_LAPTOP
If you have an MSI S270 laptop, say Y or M here.
+config DELL_LAPTOP
+ tristate "Dell Laptop Extras (EXPERIMENTAL)"
+ depends on X86
+ depends on EXPERIMENTAL
+ depends on BACKLIGHT_CLASS_DEVICE
+ ---help---
+ This driver implements LCD backlight control for Dell laptops. BEFORE
+ using this driver, please fill in your laptop model parameters as described
+ in dell-laptop.txt. Using this driver without doing this operation
+ may have UNPREDICTABLE effects on your laptop. You have been warned!
+
+ Just read <file:Documentation/dell-laptop.txt> first.
+
+ If you have a Dell laptop, say Y or M here.
+
config SONY_LAPTOP
tristate "Sony Laptop Extras"
depends on X86 && ACPI
Matt Domsch wrote:
> On Sun, Oct 28, 2007 at 07:06:23PM +0100, [email protected] wrote:
>> Matt Domsch wrote:
>>> On Sun, Oct 28, 2007 at 05:12:37PM +0100, [email protected] wrote:
>>>> Hello,
>>>> this driver implements backlight control on Dell laptops
>>>> which use SMI for changing brightness levels.
>>>>
>>>> The driver is INCOMPLETE since it is unable to probe some required
>>>> parameters
>>>> in order to perform backlight control. Such parameters are found in a Dell
>>>> proprietary DMI table which should be parsed. For now external tools may
>>>> be
>>>> used to find these parameters by hand. So if you intend to try this out,
>>>> FIRST write your laptop model parameters correctly inside the source code
>>>> as explained in Documentation/dell-laptop.txt.
>>>>
>>>> Parts of this driver may also be used to provide additional
>>>> functionalities
>>>> similarly to the drivers/misc/*-laptop.c drivers.
>>> Why is this better done in the kernel rather than in userspace with
>>> libsmbios as you've noted?
>>>
>> I had to do a kernelspace driver for controlling the backlight. This
>> was part of a college project assignment. In order for it to be valid
>> for an operating system course, it had to be in kernelspace (not
>> Unix programming) :).
>>
>> As i mentioned that can be done in userspace and it IS sensible to do
>> so. I know that the code which was already written for Dell implied
>> a userspace approach, but i simply had no choice.
>>
>> I also don't expect this driver to become mainstream, but since i have
>> written it, other people might want to have a look at it.
>
> OK, that's fair.
>
>
>> Finally i really don't think there's any sensible way of implementing
>> Linux LCD Backlight Abstraction relying on a userspace application.
>> That would mean the kernel calling userspace code to change the
>> brightness, then this latter code would again call the kernel to trigger
>> a SMI and so on. That's just not a good design. I think a userspace
>> solution implies choosing NOT to implement the LCD Abstraction. Causing
>> Dell laptops to be treated differently from other machines (as they are
>> not compliant with Linux's own interface).
>
> I've had this discussion on lkml before. Short story is, until Dell
> laptops implement the ACPI methods that the backlight API expects, the
> only sane way to do it is to let libsmbios handle it. Moving the
> fairly large and complex libsmbios into the kernel isn't a good idea
> (imho).
>
>
>
I agree. The problem is that Dell's DMI tables are not defined in the
SMBIOS standard. Thus getting the parameters required for the backlight
control (io port, io code, location) needs to be dealt with specifically.
Plus DMI is not as comprehensively supported as ACPI is under Linux.
I think reading Dell's tables to find out backlight parameters in
kernelspace is possible. Unfortunately it would require a significant
amount of brand new code to be written. And i'm not sure it is worth
the effort. Libsmbios is big and complex because it is written in
proficient C++ with lots of OO abstraction. It is also portable. But
the task accomplished is simple in principle.
jacopo
On Sun, Oct 28, 2007 at 02:20:31PM -0500, Matt Domsch wrote:
> I've had this discussion on lkml before. Short story is, until Dell
> laptops implement the ACPI methods that the backlight API expects, the
> only sane way to do it is to let libsmbios handle it. Moving the
> fairly large and complex libsmbios into the kernel isn't a good idea
> (imho).
My understanding was that the current range supported the ACPI methods.
--
Matthew Garrett | [email protected]
Hi!
> > this driver implements backlight control on Dell laptops
> > which use SMI for changing brightness levels.
> >
> > The driver is INCOMPLETE since it is unable to probe some required
> > parameters
> > in order to perform backlight control. Such parameters are found in a Dell
> > proprietary DMI table which should be parsed. For now external tools may be
> > used to find these parameters by hand. So if you intend to try this out,
> > FIRST write your laptop model parameters correctly inside the source code
> > as explained in Documentation/dell-laptop.txt.
> >
> > Parts of this driver may also be used to provide additional functionalities
> > similarly to the drivers/misc/*-laptop.c drivers.
>
> Why is this better done in the kernel rather than in userspace with
> libsmbios as you've noted?
Well, keeping the same interface as other notebooks has some
advantages... and means that kernel does its job - hw abstraction.
Pavel
--
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html