From: Daniel Vetter Date: Wed, 14 Nov 2012 16:47:39 +0000 (+0100) Subject: drm/i915: drop buggy write to FDI_RX_CHICKEN register X-Git-Tag: next-20121205~75^2^2~29 X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=607a6f7a6621f65706ff536b2615ee65b5c2f575;p=karo-tx-linux.git drm/i915: drop buggy write to FDI_RX_CHICKEN register 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 Reviewed-by: Chris Wilson [danvet: Dropped a bogus ~ from the commit message that somehow crept in.] Signed-off-by: Daniel Vetter --- diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c index 6301d0cb45ee..3e41f46cf222 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); }