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drm/edid: Ignore bad standard timings. 

Signed-off-by: Adam Jackson <ajax@redhat.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
hifive-unleashed-5.1
Adam Jackson 2009-09-23 17:30:58 -04:00 committed by Dave Airlie
parent 083ae0560a
commit 23425caeeb
1 changed files with 16 additions and 0 deletions
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16
drivers/gpu/drm/drm_edid.c
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@ -502,6 +502,19 @@ static struct drm_display_mode *drm_find_dmt(struct drm_device *dev,
}
return mode;
}
/*
* 0 is reserved. The spec says 0x01 fill for unused timings. Some old
* monitors fill with ascii space (0x20) instead.
*/
static int
bad_std_timing(u8 a, u8 b)
{
return (a == 0x00 && b == 0x00) ||
(a == 0x01 && b == 0x01) ||
(a == 0x20 && b == 0x20);
}
/**
* drm_mode_std - convert standard mode info (width, height, refresh) into mode
* @t: standard timing params
@ -525,6 +538,9 @@ struct drm_display_mode *drm_mode_std(struct drm_device *dev,
unsigned vfreq = (t->vfreq_aspect & EDID_TIMING_VFREQ_MASK)
>> EDID_TIMING_VFREQ_SHIFT;
if (bad_std_timing(t->hsize, t->vfreq_aspect))
return NULL;
/* According to the EDID spec, the hdisplay = hsize * 8 + 248 */
hsize = t->hsize * 8 + 248;
/* vrefresh_rate = vfreq + 60 */