From: Ville Syrjälä <ville.syrj...@linux.intel.com> DP link retraining causes (spurious?) underruns. We can't really avoid them, except perhaps by doing a full modeset (which has its own underrun suppression anyway). So let's just hide them.
MST still has its own logic for retrainin, but a bigger hpd handling cleanup/unification is needed there anyway, so let's leave that be for now. References: https://bugs.freedesktop.org/show_bug.cgi?id=98251 Signed-off-by: Ville Syrjälä <ville.syrj...@linux.intel.com> --- drivers/gpu/drm/i915/intel_dp.c | 29 +++++++++++++++++++++++++++-- 1 file changed, 27 insertions(+), 2 deletions(-) diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c index bc03f61d94f1..780691a34133 100644 --- a/drivers/gpu/drm/i915/intel_dp.c +++ b/drivers/gpu/drm/i915/intel_dp.c @@ -3988,6 +3988,31 @@ go_again: } static void +intel_dp_retrain_link(struct intel_dp *intel_dp) +{ + struct intel_encoder *encoder = &dp_to_dig_port(intel_dp)->base; + struct drm_i915_private *dev_priv = to_i915(encoder->base.dev); + struct intel_crtc *crtc = to_intel_crtc(encoder->base.crtc); + + /* Suppress underruns caused by re-training */ + intel_set_cpu_fifo_underrun_reporting(dev_priv, crtc->pipe, false); + if (crtc->config->has_pch_encoder) + intel_set_pch_fifo_underrun_reporting(dev_priv, + intel_crtc_pch_transcoder(crtc), false); + + intel_dp_start_link_train(intel_dp); + intel_dp_stop_link_train(intel_dp); + + /* Keep underrun reporting disabled until things are stable */ + intel_wait_for_vblank(&dev_priv->drm, crtc->pipe); + + intel_set_cpu_fifo_underrun_reporting(dev_priv, crtc->pipe, true); + if (crtc->config->has_pch_encoder) + intel_set_pch_fifo_underrun_reporting(dev_priv, + intel_crtc_pch_transcoder(crtc), true); +} + +static void intel_dp_check_link_status(struct intel_dp *intel_dp) { struct intel_encoder *intel_encoder = &dp_to_dig_port(intel_dp)->base; @@ -4012,8 +4037,8 @@ intel_dp_check_link_status(struct intel_dp *intel_dp) (!drm_dp_channel_eq_ok(link_status, intel_dp->lane_count))) { DRM_DEBUG_KMS("%s: channel EQ not ok, retraining\n", intel_encoder->base.name); - intel_dp_start_link_train(intel_dp); - intel_dp_stop_link_train(intel_dp); + + intel_dp_retrain_link(intel_dp); } } -- 2.7.4 _______________________________________________ Intel-gfx mailing list Intel-gfx@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/intel-gfx
