drm/i915: Ensure that the crtcinfo is populated during mode_fixup()

This should fix the mysterious mode setting failures reported during
boot up and after resume, generally for i8xx class machines.

Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=16478
Reported-and-tested-by: Xavier Chantry <chantry.xavier@gmail.com>
Buzilla: https://bugs.freedesktop.org/show_bug.cgi?id=29413
Tested-by: Daniel Vetter <daniel@ffwll.ch>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: stable@kernel.org

1 files changed, 8 insertions, 0 deletions

diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index 19daead5b525..b5bf51a4502d 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -2463,11 +2463,19 @@ static bool intel_crtc_mode_fixup(struct drm_crtc *crtc,
                                   struct drm_display_mode *adjusted_mode)
 {
         struct drm_device *dev = crtc->dev;
+
         if (HAS_PCH_SPLIT(dev)) {
                 /* FDI link clock is fixed at 2.7G */
                 if (mode->clock * 3 > IRONLAKE_FDI_FREQ * 4)
                         return false;
         }
+
+        /* XXX some encoders set the crtcinfo, others don't.
+         * Obviously we need some form of conflict resolution here...
+         */
+        if (adjusted_mode->crtc_htotal == 0)
+                drm_mode_set_crtcinfo(adjusted_mode, 0);
+
         return true;
 }