Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753173AbYLAQ4Z (ORCPT ); Mon, 1 Dec 2008 11:56:25 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751370AbYLAQ4O (ORCPT ); Mon, 1 Dec 2008 11:56:14 -0500 Received: from rtr.ca ([76.10.145.34]:37553 "EHLO mail.rtr.ca" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751253AbYLAQ4N (ORCPT ); Mon, 1 Dec 2008 11:56:13 -0500 Message-ID: <4934176F.6080900@rtr.ca> Date: Mon, 01 Dec 2008 11:57:19 -0500 From: Mark Lord Organization: Real-Time Remedies Inc. User-Agent: Thunderbird 2.0.0.18 (X11/20081125) MIME-Version: 1.0 To: Len Brown , Alessandro Zummo Cc: David Brownell , lkml , rtc-linux@googlegroups.com, linux-acpi@vger.kernel.org Subject: PATCH: /proc/acpi/alarm: handle day-of-month wraparound on readback References: <200806222042.13929.david-b@pacbell.net> In-Reply-To: <200806222042.13929.david-b@pacbell.net> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3443 Lines: 115 Fix month wrap issue with readback from /proc/acpi/alarm This bug has been around *forever*. $ echo '2008-12-01 10:36:20' > /proc/acpi/alarm $ cat /proc/acpi/alarm 2008-11-01 10:36:20 Note how the readback above shows the month incorrectly. But with this patch applied, it shows the correct month (12). Patch applies/works on kernels 2.6.25.* through 2.6.27.*, and probably on earlier kernels as well. Probably best to queue it up for the next major cycle. Signed-off-by: Mark Lord --- linux-2.6.25/drivers/acpi/sleep/proc.c 2008-06-09 14:27:19.000000000 -0400 +++ linux/drivers/acpi/sleep/proc.c 2008-11-30 18:08:31.000000000 -0500 @@ -84,12 +84,15 @@ #define HAVE_ACPI_LEGACY_ALARM #endif +static u32 cmos_bcd_read(int offset, int rtc_control); + #ifdef HAVE_ACPI_LEGACY_ALARM static int acpi_system_alarm_seq_show(struct seq_file *seq, void *offset) { u32 sec, min, hr; u32 day, mo, yr, cent = 0; + u32 today = 0; unsigned char rtc_control = 0; unsigned long flags; @@ -97,38 +100,32 @@ spin_lock_irqsave(&rtc_lock, flags); - sec = CMOS_READ(RTC_SECONDS_ALARM); - min = CMOS_READ(RTC_MINUTES_ALARM); - hr = CMOS_READ(RTC_HOURS_ALARM); rtc_control = CMOS_READ(RTC_CONTROL); + sec = cmos_bcd_read(RTC_SECONDS_ALARM, rtc_control); + min = cmos_bcd_read(RTC_MINUTES_ALARM, rtc_control); + hr = cmos_bcd_read(RTC_HOURS_ALARM, rtc_control); /* If we ever get an FACP with proper values... */ - if (acpi_gbl_FADT.day_alarm) + if (acpi_gbl_FADT.day_alarm) { /* ACPI spec: only low 6 its should be cared */ day = CMOS_READ(acpi_gbl_FADT.day_alarm) & 0x3F; - else - day = CMOS_READ(RTC_DAY_OF_MONTH); + if (!(rtc_control & RTC_DM_BINARY) || RTC_ALWAYS_BCD) + BCD_TO_BIN(day); + } else + day = cmos_bcd_read(RTC_DAY_OF_MONTH, rtc_control); if (acpi_gbl_FADT.month_alarm) - mo = CMOS_READ(acpi_gbl_FADT.month_alarm); - else - mo = CMOS_READ(RTC_MONTH); + mo = cmos_bcd_read(acpi_gbl_FADT.month_alarm, rtc_control); + else { + mo = cmos_bcd_read(RTC_MONTH, rtc_control); + today = cmos_bcd_read(RTC_DAY_OF_MONTH, rtc_control); + } if (acpi_gbl_FADT.century) - cent = CMOS_READ(acpi_gbl_FADT.century); + cent = cmos_bcd_read(acpi_gbl_FADT.century, rtc_control); - yr = CMOS_READ(RTC_YEAR); + yr = cmos_bcd_read(RTC_YEAR, rtc_control); spin_unlock_irqrestore(&rtc_lock, flags); - if (!(rtc_control & RTC_DM_BINARY) || RTC_ALWAYS_BCD) { - BCD_TO_BIN(sec); - BCD_TO_BIN(min); - BCD_TO_BIN(hr); - BCD_TO_BIN(day); - BCD_TO_BIN(mo); - BCD_TO_BIN(yr); - BCD_TO_BIN(cent); - } - /* we're trusting the FADT (see above) */ if (!acpi_gbl_FADT.century) /* If we're not trusting the FADT, we should at least make it @@ -153,6 +150,20 @@ else yr += cent * 100; + /* + * Show correct dates for alarms up to a month into the future. + * This solves issues for nearly all situations with the common + * 30-day alarm clocks in PC hardware. + */ + if (day < today) { + if (mo < 12) { + mo += 1; + } else { + mo = 1; + yr += 1; + } + } + seq_printf(seq, "%4.4u-", yr); (mo > 12) ? seq_puts(seq, "**-") : seq_printf(seq, "%2.2u-", mo); (day > 31) ? seq_puts(seq, "** ") : seq_printf(seq, "%2.2u ", day); -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/