drm/i915: Apply display workaround required according to the B-Spec.

Not known to fix any current bugs.

Signed-off-by: Eric Anholt <eric@anholt.net>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>

1 files changed, 4 insertions, 0 deletions

diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index 5ab40355684..c41dae5ade3 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -5819,6 +5819,10 @@ void intel_init_clock_gating(struct drm_device *dev)
                                    ILK_CLK_FBC);
                 }
 
+                I915_WRITE(ILK_DISPLAY_CHICKEN2,
+                           I915_READ(ILK_DISPLAY_CHICKEN2) |
+                           ILK_ELPIN_409_SELECT);
+
                 if (IS_GEN5(dev)) {
                         I915_WRITE(_3D_CHICKEN2,
                                    _3D_CHICKEN2_WM_READ_PIPELINED << 16 |