On Sat, 8 Dec 2012 12:58:33 +0100 Daniel Vetter <daniel.vet...@ffwll.ch> wrote:
> We've originally added this in > > commit 291427f5fdadec6e4be2924172e83588880e1539 > Author: Jesse Barnes <jbar...@virtuousgeek.org> > Date: Fri Jul 29 12:42:37 2011 -0700 > > drm/i915: apply phase pointer override on SNB+ too > > and then copy-pasted it over to ivb/ppt. The w/a was originally added > for ilk/ibx in > > commit 5b2adf897146edeac6a1e438fb67b5a53dbbdf34 > Author: Jesse Barnes <jbar...@virtuousgeek.org> > Date: Thu Oct 7 16:01:15 2010 -0700 > > drm/i915: add Ironlake clock gating workaround for FDI link training > > and fixed up a bit in > > commit 6f06ce184c765fd8d50669a8d12fdd566c920859 > Author: Jesse Barnes <jbar...@virtuousgeek.org> > Date: Tue Jan 4 15:09:38 2011 -0800 > > drm/i915: set phase sync pointer override enable before setting phase > sync pointer > > It turns out that this w/a isn't actually required on cpt/ppt and > positively harmful on ivb/ppt when using fdi B/C links - it results in > a black screen occasionally, with seemingfully everything working as > it should. The only failure indication I've found in the hw is that > eventually (but not right after the modeset completes) a pipe underrun > is signalled. > > Big thanks to Arthur Runyan for all the ideas for registers to check > and changes to test, otherwise I couldn't ever have tracked this down! > > Cc: "Runyan, Arthur J" <arthur.j.run...@intel.com> > Cc: stable@vger.kernel.org > Signed-off-by: Daniel Vetter <daniel.vet...@ffwll.ch> > --- > drivers/gpu/drm/i915/intel_display.c | 29 ----------------------------- > 1 file changed, 29 deletions(-) > > diff --git a/drivers/gpu/drm/i915/intel_display.c > b/drivers/gpu/drm/i915/intel_display.c > index b29259a..6929104 100644 > --- a/drivers/gpu/drm/i915/intel_display.c > +++ b/drivers/gpu/drm/i915/intel_display.c > @@ -2335,18 +2335,6 @@ static void intel_fdi_normal_train(struct drm_crtc > *crtc) > FDI_FE_ERRC_ENABLE); > } > > -static void cpt_phase_pointer_enable(struct drm_device *dev, int pipe) > -{ > - struct drm_i915_private *dev_priv = dev->dev_private; > - u32 flags = I915_READ(SOUTH_CHICKEN1); > - > - flags |= FDI_PHASE_SYNC_OVR(pipe); > - I915_WRITE(SOUTH_CHICKEN1, flags); /* once to unlock... */ > - flags |= FDI_PHASE_SYNC_EN(pipe); > - I915_WRITE(SOUTH_CHICKEN1, flags); /* then again to enable */ > - POSTING_READ(SOUTH_CHICKEN1); > -} > - > static void ivb_modeset_global_resources(struct drm_device *dev) > { > struct drm_i915_private *dev_priv = dev->dev_private; > @@ -2521,8 +2509,6 @@ static void gen6_fdi_link_train(struct drm_crtc *crtc) > POSTING_READ(reg); > udelay(150); > > - cpt_phase_pointer_enable(dev, pipe); > - > for (i = 0; i < 4; i++) { > reg = FDI_TX_CTL(pipe); > temp = I915_READ(reg); > @@ -2655,8 +2641,6 @@ static void ivb_manual_fdi_link_train(struct drm_crtc > *crtc) > POSTING_READ(reg); > udelay(150); > > - cpt_phase_pointer_enable(dev, pipe); > - > for (i = 0; i < 4; i++) { > reg = FDI_TX_CTL(pipe); > temp = I915_READ(reg); > @@ -2791,17 +2775,6 @@ static void ironlake_fdi_pll_disable(struct intel_crtc > *intel_crtc) > udelay(100); > } > > -static void cpt_phase_pointer_disable(struct drm_device *dev, int pipe) > -{ > - struct drm_i915_private *dev_priv = dev->dev_private; > - u32 flags = I915_READ(SOUTH_CHICKEN1); > - > - flags &= ~(FDI_PHASE_SYNC_EN(pipe)); > - I915_WRITE(SOUTH_CHICKEN1, flags); /* once to disable... */ > - flags &= ~(FDI_PHASE_SYNC_OVR(pipe)); > - I915_WRITE(SOUTH_CHICKEN1, flags); /* then again to lock */ > - POSTING_READ(SOUTH_CHICKEN1); > -} > static void ironlake_fdi_disable(struct drm_crtc *crtc) > { > struct drm_device *dev = crtc->dev; > @@ -2828,8 +2801,6 @@ 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); > - } else if (HAS_PCH_CPT(dev)) { > - cpt_phase_pointer_disable(dev, pipe); > } > > /* still set train pattern 1 */ Reviewed-by: Jesse Barnes <jbar...@virtuousgeek.org> -- Jesse Barnes, Intel Open Source Technology Center -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html