Re: [PATCH] fbdev: fix parsing of standard timings
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From: Florian Tobias Schandinat <FlorianSchandinat@gmx.de>
Date: 2011-09-01 13:10:28
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:quoted
Hi Tomi, On 08/26/2011 12:38 PM, Tomi Valkeinen wrote:quoted
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 <redacted>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
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From 82c630291ad39d45009352fce1b23b4d0f44f92d Mon Sep 17 00:00:00 2001From: Tomi Valkeinen <redacted> 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 <redacted> --- 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 */