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KMS: fix EDID detailed timing vsync parsing 

EDID spreads some values across multiple bytes; bit-fiddling is needed
to retrieve these.  The current code to parse "detailed timings" has a
cut&paste error that results in a vsync offset of at most 15 lines
instead of 63.

See

   http://en.wikipedia.org/wiki/EDID

and in the "EDID Detailed Timing Descriptor" see bytes 10+11 show why
that needs to be a left shift.

Cc: stable@vger.kernel.org
Signed-off-by: Torsten Duwe <duwe@lst.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
hifive-unleashed-5.1
Torsten Duwe 2013-03-23 15:38:22 +01:00 committed by Linus Torvalds
parent 5da273fe3f
commit 16dad1d743
1 changed files with 1 additions and 1 deletions
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2
drivers/gpu/drm/drm_edid.c
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@ -1634,7 +1634,7 @@ static struct drm_display_mode *drm_mode_detailed(struct drm_device *dev,
unsigned vblank = (pt->vactive_vblank_hi & 0xf) << 8 | pt->vblank_lo;
unsigned hsync_offset = (pt->hsync_vsync_offset_pulse_width_hi & 0xc0) << 2 | pt->hsync_offset_lo;
unsigned hsync_pulse_width = (pt->hsync_vsync_offset_pulse_width_hi & 0x30) << 4 | pt->hsync_pulse_width_lo;
unsigned vsync_offset = (pt->hsync_vsync_offset_pulse_width_hi & 0xc) >> 2 | pt->vsync_offset_pulse_width_lo >> 4;
unsigned vsync_offset = (pt->hsync_vsync_offset_pulse_width_hi & 0xc) << 2 | pt->vsync_offset_pulse_width_lo >> 4;
unsigned vsync_pulse_width = (pt->hsync_vsync_offset_pulse_width_hi & 0x3) << 4 | (pt->vsync_offset_pulse_width_lo & 0xf);
/* ignore tiny modes */