drm/i915: Make sure vsyncshift is positive

If vsyncshift comes out as negative, add one htotal to it to get the
corresponding positive value.

This is rather theoretical as it would require a mode where the
hsync+back porch is very long and the active+front porch very short.

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
This commit is contained in:
Ville Syrjälä 2014-03-28 23:29:32 +02:00 committed by Daniel Vetter
parent efc2cfff28
commit 1caea6e945

View file

@ -5369,7 +5369,8 @@ static void intel_set_pipe_timings(struct intel_crtc *intel_crtc)
enum transcoder cpu_transcoder = intel_crtc->config.cpu_transcoder;
struct drm_display_mode *adjusted_mode =
&intel_crtc->config.adjusted_mode;
uint32_t vsyncshift = 0, crtc_vtotal, crtc_vblank_end;
uint32_t crtc_vtotal, crtc_vblank_end;
int vsyncshift = 0;
/* We need to be careful not to changed the adjusted mode, for otherwise
* the hw state checker will get angry at the mismatch. */
@ -5386,6 +5387,8 @@ static void intel_set_pipe_timings(struct intel_crtc *intel_crtc)
else
vsyncshift = adjusted_mode->crtc_hsync_start -
adjusted_mode->crtc_htotal / 2;
if (vsyncshift < 0)
vsyncshift += adjusted_mode->crtc_htotal;
}
if (INTEL_INFO(dev)->gen > 3)