On 08/30/2011 05:31 AM, Tomi Valkeinen wrote:
> Hi Florian,
>
> On Fri, 2011-08-26 at 18:02 +0000, Florian Tobias Schandinat wrote:
>> Hi Tomi,
>>
>> On 08/26/2011 12:38 PM, Tomi Valkeinen wrote:
>>> The standard timings parses uses 1:1 dimensions when the ratio in the
>>> EDID data is 0. However, for EDID 1.3 and later the dimensions are 16:10
>>> when the ratio is 0.
>>>
>>> Pass the version and revision numbers to get_std_timing() which can then
>>> make the right decision about dimensions.
>>>
>>> Signed-off-by: Tomi Valkeinen <tomi.valkeinen@xxxxxx>
>>
>> Thanks, looks good to me.
>> I'd be happy if someone with access to the original EDID specs could confirm
>> this and add his reviewed by.
>> I also think adding a comment explaining this change would be helpful.
>
> You can see the same thing done in
> drivers/gpu/drm/drm_edid.c:drm_mode_std(). Although they seem to check
> only revision, which looks a bit risky to me.
>
> The specs seem to be available by just googling them, although I don't
> know if it's legal to distribute them or not...
>
> I've added your comment, I agree it's good. Patch below.
Looks like your googling is better than mine, I only found references to it.
Anyway, I've applied this patch.
Thanks,
Florian Tobias Schandinat
>
> Tomi
>
>
>>From 82c630291ad39d45009352fce1b23b4d0f44f92d Mon Sep 17 00:00:00 2001
> From: Tomi Valkeinen <tomi.valkeinen@xxxxxx>
> Date: Thu, 25 Aug 2011 15:36:40 +0300
> Subject: [PATCH] fbdev: fix parsing of standard timings
>
> The standard timings parses uses 1:1 dimensions when the ratio in the
> EDID data is 0. However, for EDID 1.3 and later the dimensions are 16:10
> when the ratio is 0.
>
> Pass the version and revision numbers to get_std_timing() which can then
> make the right decision about dimensions.
>
> Signed-off-by: Tomi Valkeinen <tomi.valkeinen@xxxxxx>
> ---
> drivers/video/fbmon.c | 21 +++++++++++++++------
> 1 files changed, 15 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/video/fbmon.c b/drivers/video/fbmon.c
> index 4f57485..cef6557 100644
> --- a/drivers/video/fbmon.c
> +++ b/drivers/video/fbmon.c
> @@ -493,7 +493,8 @@ static int get_est_timing(unsigned char *block, struct fb_videomode *mode)
> return num;
> }
>
> -static int get_std_timing(unsigned char *block, struct fb_videomode *mode)
> +static int get_std_timing(unsigned char *block, struct fb_videomode *mode,
> + int ver, int rev)
> {
> int xres, yres = 0, refresh, ratio, i;
>
> @@ -504,7 +505,11 @@ static int get_std_timing(unsigned char *block, struct fb_videomode *mode)
> ratio = (block[1] & 0xc0) >> 6;
> switch (ratio) {
> case 0:
> - yres = xres;
> + /* in EDID 1.3 the meaning of 0 changed to 16:10 (prior 1:1) */
> + if (ver < 1 || (ver == 1 && rev < 3))
> + yres = xres;
> + else
> + yres = (xres * 10)/16;
> break;
> case 1:
> yres = (xres * 3)/4;
> @@ -533,12 +538,12 @@ static int get_std_timing(unsigned char *block, struct fb_videomode *mode)
> }
>
> static int get_dst_timing(unsigned char *block,
> - struct fb_videomode *mode)
> + struct fb_videomode *mode, int ver, int rev)
> {
> int j, num = 0;
>
> for (j = 0; j < 6; j++, block += STD_TIMING_DESCRIPTION_SIZE)
> - num += get_std_timing(block, &mode[num]);
> + num += get_std_timing(block, &mode[num], ver, rev);
>
> return num;
> }
> @@ -599,6 +604,10 @@ static struct fb_videomode *fb_create_modedb(unsigned char *edid, int *dbsize)
> struct fb_videomode *mode, *m;
> unsigned char *block;
> int num = 0, i, first = 1;
> + int ver, rev;
> +
> + ver = edid[EDID_STRUCT_VERSION];
> + rev = edid[EDID_STRUCT_REVISION];
>
> mode = kzalloc(50 * sizeof(struct fb_videomode), GFP_KERNEL);
> if (mode == NULL)
> @@ -632,12 +641,12 @@ static struct fb_videomode *fb_create_modedb(unsigned char *edid, int *dbsize)
> DPRINTK(" Standard Timings\n");
> block = edid + STD_TIMING_DESCRIPTIONS_START;
> for (i = 0; i < STD_TIMING; i++, block += STD_TIMING_DESCRIPTION_SIZE)
> - num += get_std_timing(block, &mode[num]);
> + num += get_std_timing(block, &mode[num], ver, rev);
>
> block = edid + DETAILED_TIMING_DESCRIPTIONS_START;
> for (i = 0; i < 4; i++, block+= DETAILED_TIMING_DESCRIPTION_SIZE) {
> if (block[0] == 0x00 && block[1] == 0x00 && block[3] == 0xfa)
> - num += get_dst_timing(block + 5, &mode[num]);
> + num += get_dst_timing(block + 5, &mode[num], ver, rev);
> }
>
> /* Yikes, EDID data is totally useless */
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