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[0523/1094] drm/i915: Make sure vsyncshift is positive

Message ID 1413889294-31328-524-git-send-email-dheerajx.s.jamwal@intel.com (mailing list archive)
State New, archived
Headers show

Commit Message

Dheeraj Jamwal Oct. 21, 2014, 10:52 a.m. UTC 
From: Ville Syrjälä <ville.syrjala@linux.intel.com>

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>
(cherry picked from commit 1caea6e945e0867d391369097937620c945dcec1)

Signed-off-by: Dheeraj Jamwal <dheerajx.s.jamwal@intel.com>
---
 drivers/gpu/drm/i915/intel_display.c |    5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)
diff mbox

Patch

diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index c62728d..4262300 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -5367,7 +5367,8 @@  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. */
@@ -5384,6 +5385,8 @@  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)