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drm/vblank: Enable precise vblank timestamps for interlaced and doublescan modes.

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Testing showed the current code can already handle doublescan
video modes just fine. A trivial tweak makes it work for interlaced
scanout as well.

Tested and shown to be precise on Radeon rv530, r600 and
Intel 945-GME.

Signed-off-by: Mario Kleiner <mario.kleiner@tuebingen.mpg.de>
Signed-off-by: Dave Airlie <airlied@redhat.com>
This commit is contained in:
Mario Kleiner 2011-02-21 05:42:02 +01:00 committed by Dave Airlie
parent bc21512835
commit 9be6f8a978
1 changed files with 6 additions and 8 deletions
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14
drivers/gpu/drm/drm_irq.c
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@ -493,6 +493,12 @@ void drm_calc_timestamping_constants(struct drm_crtc *crtc)
/* Dot clock in Hz: */
dotclock = (u64) crtc->hwmode.clock * 1000;
/* Fields of interlaced scanout modes are only halve a frame duration.
* Double the dotclock to get halve the frame-/line-/pixelduration.
*/
if (crtc->hwmode.flags & DRM_MODE_FLAG_INTERLACE)
dotclock *= 2;
/* Valid dotclock? */
if (dotclock > 0) {
/* Convert scanline length in pixels and video dot clock to
@ -605,14 +611,6 @@ int drm_calc_vbltimestamp_from_scanoutpos(struct drm_device *dev, int crtc,
return -EAGAIN;
}
/* Don't know yet how to handle interlaced or
* double scan modes. Just no-op for now.
*/
if (mode->flags & (DRM_MODE_FLAG_INTERLACE | DRM_MODE_FLAG_DBLSCAN)) {
DRM_DEBUG("crtc %d: Noop due to unsupported mode.\n", crtc);
return -ENOTSUPP;
}
/* Get current scanout position with system timestamp.
* Repeat query up to DRM_TIMESTAMP_MAXRETRIES times
* if single query takes longer than max_error nanoseconds.