Re: [PATCH 10/10] drm/i915: Leave FDI running after failed link training on LPT-H

["Ville Syrjälä" <ville.syrjala@linux.intel.com>]

On Wed, Dec 02, 2015 at 03:16:56PM -0200, Paulo Zanoni wrote:
> 2015-12-01 11:08 GMT-02:00  <ville.syrjala@linux.intel.com>:
> > From: Ville Syrjälä <ville.syrjala@linux.intel.com>
> >
> > Currently we disable some parts of FDI setup after a failed link
> > training. But despite that we continue with the modeset as if everything
> > is fine. This results in tons of noise from the state checker, and
> > it means we're not following the proper modeset sequence for the rest of
> > crtc enabling, nor for crtc disabling.
> >
> > Ideally we should abort the modeset and follow the proper disable
> > suquenced to shut off everything we enabled so far, but that would
    ^^^^^^^^^
And I spotted another typo, which I'll fix.

> > require a big rework of the modeset code. So instead just leave FDI
> > up and running in its untrained state, and log an error. This is
> > what we do on older platforms too.
> 
> Reviewed-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
> 
> >
> > Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
> > ---
> >  drivers/gpu/drm/i915/intel_ddi.c | 24 +++++++++++++++---------
> >  1 file changed, 15 insertions(+), 9 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/i915/intel_ddi.c b/drivers/gpu/drm/i915/intel_ddi.c
> > index 76ce7c2960b6..b312a47a0654 100644
> > --- a/drivers/gpu/drm/i915/intel_ddi.c
> > +++ b/drivers/gpu/drm/i915/intel_ddi.c
> > @@ -675,15 +675,16 @@ void hsw_fdi_link_train(struct drm_crtc *crtc)
> >                 temp = I915_READ(DP_TP_STATUS(PORT_E));
> >                 if (temp & DP_TP_STATUS_AUTOTRAIN_DONE) {
> >                         DRM_DEBUG_KMS("FDI link training done on step %d\n", i);
> > +                       break;
> > +               }
> >
> > -                       /* Enable normal pixel sending for FDI */
> > -                       I915_WRITE(DP_TP_CTL(PORT_E),
> > -                                  DP_TP_CTL_FDI_AUTOTRAIN |
> > -                                  DP_TP_CTL_LINK_TRAIN_NORMAL |
> > -                                  DP_TP_CTL_ENHANCED_FRAME_ENABLE |
> > -                                  DP_TP_CTL_ENABLE);
> > -
> > -                       return;
> > +               /*
> > +                * Leave things enabled even if we failed to train FDI.
> > +                * Results in less fireworks from the state checker.
> > +                */
> > +               if (i == ARRAY_SIZE(hsw_ddi_translations_fdi) * 2 - 1) {
> > +                       DRM_ERROR("FDI link training failed!\n");
> > +                       break;
> >                 }
> >
> >                 temp = I915_READ(DDI_BUF_CTL(PORT_E));
> > @@ -712,7 +713,12 @@ void hsw_fdi_link_train(struct drm_crtc *crtc)
> >                 POSTING_READ(FDI_RX_MISC(PIPE_A));
> >         }
> >
> > -       DRM_ERROR("FDI link training failed!\n");
> > +       /* Enable normal pixel sending for FDI */
> > +       I915_WRITE(DP_TP_CTL(PORT_E),
> > +                  DP_TP_CTL_FDI_AUTOTRAIN |
> > +                  DP_TP_CTL_LINK_TRAIN_NORMAL |
> > +                  DP_TP_CTL_ENHANCED_FRAME_ENABLE |
> > +                  DP_TP_CTL_ENABLE);
> >  }
> >
> >  void intel_ddi_init_dp_buf_reg(struct intel_encoder *encoder)
> > --
> > 2.4.10
> >
> > _______________________________________________
> > Intel-gfx mailing list
> > Intel-gfx@lists.freedesktop.org
> > http://lists.freedesktop.org/mailman/listinfo/intel-gfx
> 
> 
> 
> -- 
> Paulo Zanoni

-- 
Ville Syrjälä
Intel OTC
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