2009-03-30 22:03:13

by Michal Januszewski

Subject: [PATCH] uvesafb: fix color component length for pseudocolor modes

uvesafb incorrectly sets the length of the color fields to 6 bits
for PSEUDOCOLOR modes, even though 8 bits are always used per pixel.
Fix this by setting the length to 8.

The switch of the DAC width from the default 6 bits to 8 bits is
retained and tracked internally in the driver, but never exposed
to userspace.

Signed-off-by: Michal Januszewski <[email protected]>
Cc: Krzysztof Helt <[email protected]>
Cc: Ville Syrjälä <[email protected]>
Cc: Geert Uytterhoeven <[email protected]>
---
diff --git a/drivers/video/uvesafb.c b/drivers/video/uvesafb.c
index 74ae758..5b59198 100644
--- a/drivers/video/uvesafb.c
+++ b/drivers/video/uvesafb.c
@@ -55,6 +55,7 @@ static u16 maxvf __devinitdata; /* maximum vertical frequency */
static u16 maxhf __devinitdata; /* maximum horizontal frequency */
static u16 vbemode __devinitdata; /* force use of a specific VBE mode */
static char *mode_option __devinitdata;
+static u8 dac_width = 6;

static struct uvesafb_ktask *uvfb_tasks[UVESAFB_TASKS_MAX];
static DEFINE_MUTEX(uvfb_lock);
@@ -303,22 +304,10 @@ static void uvesafb_setup_var(struct fb_var_screeninfo *var,
var->blue.offset = 0;
var->transp.offset = 0;

- /*
- * We're assuming that we can switch the DAC to 8 bits. If
- * this proves to be incorrect, we'll update the fields
- * later in set_par().
- */
- if (par->vbe_ib.capabilities & VBE_CAP_CAN_SWITCH_DAC) {
- var->red.length = 8;
- var->green.length = 8;
- var->blue.length = 8;
- var->transp.length = 0;
- } else {
- var->red.length = 6;
- var->green.length = 6;
- var->blue.length = 6;
- var->transp.length = 0;
- }
+ var->red.length = 8;
+ var->green.length = 8;
+ var->blue.length = 8;
+ var->transp.length = 0;
}
}

@@ -1001,7 +990,7 @@ static int uvesafb_setcolreg(unsigned regno, unsigned red, unsigned green,
struct fb_info *info)
{
struct uvesafb_pal_entry entry;
- int shift = 16 - info->var.green.length;
+ int shift = 16 - dac_width;
int err = 0;

if (regno >= info->cmap.len)
@@ -1050,7 +1039,7 @@ static int uvesafb_setcolreg(unsigned regno, unsigned red, unsigned green,
static int uvesafb_setcmap(struct fb_cmap *cmap, struct fb_info *info)
{
struct uvesafb_pal_entry *entries;
- int shift = 16 - info->var.green.length;
+ int shift = 16 - dac_width;
int i, err = 0;

if (info->var.bits_per_pixel == 8) {
@@ -1312,13 +1301,9 @@ setmode:
err = uvesafb_exec(task);
if (err || (task->t.regs.eax & 0xffff) != 0x004f ||
((task->t.regs.ebx & 0xff00) >> 8) != 8) {
- /*
- * We've failed to set the DAC palette format -
- * time to correct var.
- */
- info->var.red.length = 6;
- info->var.green.length = 6;
- info->var.blue.length = 6;
+ dac_width = 6;
+ } else {
+ dac_width = 8;
}
}

2009-04-01 17:53:42

by Krzysztof Helt

Subject: Re: [PATCH] uvesafb: fix color component length for pseudocolor modes

On Tue, 31 Mar 2009 00:02:46 +0200
Michal Januszewski <[email protected]> wrote:

> uvesafb incorrectly sets the length of the color fields to 6 bits
> for PSEUDOCOLOR modes, even though 8 bits are always used per pixel.
> Fix this by setting the length to 8.
>
> The switch of the DAC width from the default 6 bits to 8 bits is
> retained and tracked internally in the driver, but never exposed
> to userspace.
>
> Signed-off-by: Michal Januszewski <[email protected]>
> Cc: Krzysztof Helt <[email protected]>
> Cc: Ville Syrj?l? <[email protected]>
> Cc: Geert Uytterhoeven <[email protected]>
> ---

Acked-by: Krzysztof Helt <[email protected]>



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