Instead of direct calls of the link training functions, use a modeset
commit to retrain a DP link in SST mode, similarly to how this is done
in DP-MST mode. Originally the current way was chosen presumedly,
because there wasn't a well-established way in place for the driver to
do an internal (vs. userspace/kernel client) commit. Since then such
internal commits became a common place (initial-, HDMI/TC link reset
commit), so there is no reason to handle the DP-SST link-retraining case
differently.
At the end of the current sequence the HW reported a FIFO underrun -
without other issues visible to users - because during retraining the
link's encoder/port was disabled/re-enabled without also
disabling/re-enabling the corresponding pipe/transcoder (as required by
the spec); the corresponding underrun error message was suppressed as a
known issue. Based on Ankit's test on DG2 the underrun error was still
reported as it got detected with some (vblank) delay wrt. other
platforms. Switching to a modeset commit resolves these underrun related
issues.
Cc: Ankit Nautiyal <ankit.k.nautiyal@xxxxxxxxx>
Cc: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx>
Signed-off-by: Imre Deak <imre.deak@xxxxxxxxx>
---
drivers/gpu/drm/i915/display/intel_dp.c | 67 ++++---------------------
1 file changed, 9 insertions(+), 58 deletions(-)
diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c
index d4b1b18453dca..f83128ac60756 100644
--- a/drivers/gpu/drm/i915/display/intel_dp.c
+++ b/drivers/gpu/drm/i915/display/intel_dp.c
@@ -5242,8 +5242,6 @@ static int intel_dp_retrain_link(struct intel_encoder *encoder,
{
struct drm_i915_private *dev_priv = to_i915(encoder->base.dev);
struct intel_dp *intel_dp = enc_to_intel_dp(encoder);
- struct intel_crtc *crtc;
- bool mst_output = false;
u8 pipe_mask;
int ret;
@@ -5272,64 +5270,17 @@ static int intel_dp_retrain_link(struct intel_encoder *encoder,
encoder->base.base.id, encoder->base.name,
str_yes_no(intel_dp->link.force_retrain));
- for_each_intel_crtc_in_pipe_mask(&dev_priv->drm, crtc, pipe_mask) {
- const struct intel_crtc_state *crtc_state =
- to_intel_crtc_state(crtc->base.state);
+ ret = intel_modeset_commit_pipes(dev_priv, pipe_mask, ctx);
+ if (ret == -EDEADLK)
+ return ret;
- if (intel_crtc_has_type(crtc_state, INTEL_OUTPUT_DP_MST)) {
- mst_output = true;
- break;
- }
+ intel_dp->link.force_retrain = false;
- /* Suppress underruns caused by re-training */
- intel_set_cpu_fifo_underrun_reporting(dev_priv, crtc->pipe, false);
- if (crtc_state->has_pch_encoder)
- intel_set_pch_fifo_underrun_reporting(dev_priv,
- intel_crtc_pch_transcoder(crtc), false);
- }
-
- /* TODO: use a modeset for SST as well. */
- if (mst_output) {
- ret = intel_modeset_commit_pipes(dev_priv, pipe_mask, ctx);
-
- if (ret && ret != -EDEADLK)
- drm_dbg_kms(&dev_priv->drm,
- "[ENCODER:%d:%s] link retraining failed: %pe\n",
- encoder->base.base.id, encoder->base.name,
- ERR_PTR(ret));
-
- goto out;
- }
-
- for_each_intel_crtc_in_pipe_mask(&dev_priv->drm, crtc, pipe_mask) {
- const struct intel_crtc_state *crtc_state =
- to_intel_crtc_state(crtc->base.state);
-
- intel_dp->link_trained = false;
-
- intel_dp_check_frl_training(intel_dp);
- intel_dp_pcon_dsc_configure(intel_dp, crtc_state);
- intel_dp_start_link_train(NULL, intel_dp, crtc_state);
- intel_dp_stop_link_train(intel_dp, crtc_state);
- break;
- }
-
- for_each_intel_crtc_in_pipe_mask(&dev_priv->drm, crtc, pipe_mask) {
- const struct intel_crtc_state *crtc_state =
- to_intel_crtc_state(crtc->base.state);
-
- /* Keep underrun reporting disabled until things are stable */
- intel_crtc_wait_for_next_vblank(crtc);
-
- intel_set_cpu_fifo_underrun_reporting(dev_priv, crtc->pipe, true);
- if (crtc_state->has_pch_encoder)
- intel_set_pch_fifo_underrun_reporting(dev_priv,
- intel_crtc_pch_transcoder(crtc), true);
- }
-
-out:
- if (ret != -EDEADLK)
- intel_dp->link.force_retrain = false;
+ if (ret)
+ drm_dbg_kms(&dev_priv->drm,
+ "[ENCODER:%d:%s] link retraining failed: %pe\n",
+ encoder->base.base.id, encoder->base.name,
+ ERR_PTR(ret));
return ret;
}
--
2.44.2
