Jani Nikula noticed that the parentheses are wrong and we & the bit with the register address instead of the read-back value. He sent a patch to correct that. On second look, we write the same register in the previous line, and the w/a seems to be to set FDI_RX_PHASE_SYNC_POINTER_OVR to enable the logic, then keep always set FDI_RX_PHASE_SYNC_POINTER_OVR and toggle ~FDI_RX_PHASE_SYNC_POINTER_EN before/after enabling the pc transcoder. So the right things seems to be to simply kill the 2nd write. Cc: Jani Nikula <jani.nikula at intel.com> Signed-off-by: Daniel Vetter <daniel.vetter at ffwll.ch> --- drivers/gpu/drm/i915/intel_display.c | 3 --- 1 file changed, 3 deletions(-) diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c index f95d537..ed79e51 100644 --- a/drivers/gpu/drm/i915/intel_display.c +++ b/drivers/gpu/drm/i915/intel_display.c @@ -2924,9 +2924,6 @@ static void ironlake_fdi_disable(struct drm_crtc *crtc) /* Ironlake workaround, disable clock pointer after downing FDI */ if (HAS_PCH_IBX(dev)) { I915_WRITE(FDI_RX_CHICKEN(pipe), FDI_RX_PHASE_SYNC_POINTER_OVR); - I915_WRITE(FDI_RX_CHICKEN(pipe), - I915_READ(FDI_RX_CHICKEN(pipe) & - ~FDI_RX_PHASE_SYNC_POINTER_EN)); } else if (HAS_PCH_CPT(dev)) { cpt_phase_pointer_disable(dev, pipe); } -- 1.7.11.4