From: Chris Wilson <chris@chris-wilson.co.uk>
Date: Thu, 21 Jun 2012 10:19:59 +0000 (+0300)
Subject: drm/i915: Cantiga+ cannot handle a hsync front porch of 0
X-Git-Url: http://git.lede-project.org./?a=commitdiff_plain;h=44f46b4222a9ba5b21dcdf13f93dc53f48768d2b;p=openwrt%2Fstaging%2Fblogic.git

drm/i915: Cantiga+ cannot handle a hsync front porch of 0

This addresses WaPruneModeWithIncorrectHsyncOffset.

Bugzilla: http://bugs.freedesktop.org/show_bug.cgi?id=50236
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
---

diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index 42c57581c53f..778cbb88bddc 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -3602,6 +3602,13 @@ static bool intel_crtc_mode_fixup(struct drm_crtc *crtc,
 	if (!(adjusted_mode->private_flags & INTEL_MODE_CRTC_TIMINGS_SET))
 		drm_mode_set_crtcinfo(adjusted_mode, 0);
 
+	/* WaPruneModeWithIncorrectHsyncOffset: Cantiga+ cannot handle modes
+	 * with a hsync front porch of 0.
+	 */
+	if ((INTEL_INFO(dev)->gen > 4 || IS_G4X(dev)) &&
+		adjusted_mode->hsync_start == adjusted_mode->hdisplay)
+		return false;
+
 	return true;
 }