| Date | Mon, 25 Mar 2013 01:07:06 +0000 | From | Ben Hutchings <> | Subject | [ 102/104] KMS: fix EDID detailed timing vsync parsing |
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3.2-stable review patch. If anyone has any objections, please let me know.
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From: Torsten Duwe <torsten@lst.de>
commit 16dad1d743d31a104a849c8944e6b9eb479f6cd7 upstream.
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.
Signed-off-by: Torsten Duwe <duwe@lst.de> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Ben Hutchings <ben@decadent.org.uk> --- drivers/gpu/drm/drm_edid.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- a/drivers/gpu/drm/drm_edid.c +++ b/drivers/gpu/drm/drm_edid.c @@ -852,7 +852,7 @@ static struct drm_display_mode *drm_mode 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 */
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