On Mon, May 20, 2024 at 09:58:12PM +0300, Imre Deak wrote: > After a link training failure if the link parameters can't be further > reduced, there is no point in trying to retrain the link in the driver. > This avoids excessive retrain attempts after detecting a bad link, for > instance while handling MST HPD IRQs, which is likely redundant as the > link training failed already twice with the same minimum link > parameters. Userspace can still try to retrain the link with these > parameters via a modeset. > > While at it make the error message more accurate and emit instead a > debug message if the link training failure was only forced for testing > purposes. > > Signed-off-by: Imre Deak <[email protected]> > --- > .../drm/i915/display/intel_display_types.h | 1 + > drivers/gpu/drm/i915/display/intel_dp.c | 4 ++++ > .../drm/i915/display/intel_dp_link_training.c | 22 +++++++++++++------ > 3 files changed, 20 insertions(+), 7 deletions(-) > > diff --git a/drivers/gpu/drm/i915/display/intel_display_types.h > b/drivers/gpu/drm/i915/display/intel_display_types.h > index bde518c843468..eb0cac3e27acf 100644 > --- a/drivers/gpu/drm/i915/display/intel_display_types.h > +++ b/drivers/gpu/drm/i915/display/intel_display_types.h > @@ -1765,6 +1765,7 @@ struct intel_dp { > int max_lane_count; > /* Max rate for the current link */ > int max_rate; > + bool retrain_disabled; > /* Sequential link training failures after a passing LT */ > int seq_train_failures; > } link; > diff --git a/drivers/gpu/drm/i915/display/intel_dp.c > b/drivers/gpu/drm/i915/display/intel_dp.c > index b72dbd7becb74..34d64fe3302ef 100644 > --- a/drivers/gpu/drm/i915/display/intel_dp.c > +++ b/drivers/gpu/drm/i915/display/intel_dp.c > @@ -2950,6 +2950,7 @@ static void intel_dp_reset_link_params(struct intel_dp > *intel_dp) > { > intel_dp->link.max_lane_count = > intel_dp_max_common_lane_count(intel_dp); > intel_dp->link.max_rate = intel_dp_max_common_rate(intel_dp); > + intel_dp->link.retrain_disabled = false; > intel_dp->link.seq_train_failures = 0; > } > > @@ -5061,6 +5062,9 @@ intel_dp_needs_link_retrain(struct intel_dp *intel_dp) > intel_dp->lane_count)) > return false; > > + if (intel_dp->link.retrain_disabled) > + return false; > + > if (intel_dp->link.seq_train_failures) > return true; > > diff --git a/drivers/gpu/drm/i915/display/intel_dp_link_training.c > b/drivers/gpu/drm/i915/display/intel_dp_link_training.c > index 97d499e4b6ef7..375f59afd4dec 100644 > --- a/drivers/gpu/drm/i915/display/intel_dp_link_training.c > +++ b/drivers/gpu/drm/i915/display/intel_dp_link_training.c > @@ -1165,10 +1165,8 @@ static int > intel_dp_get_link_train_fallback_values(struct intel_dp *intel_dp, > new_link_rate = intel_dp_max_common_rate(intel_dp); > } > > - if (new_lane_count < 0) { > - drm_err(&i915->drm, "Link Training Unsuccessful\n"); > + if (new_lane_count < 0) > return -1; > - } > > if (intel_dp_is_edp(intel_dp) && > !intel_dp_can_link_train_fallback_for_edp(intel_dp, new_link_rate, > new_lane_count)) { > @@ -1187,7 +1185,7 @@ static int > intel_dp_get_link_train_fallback_values(struct intel_dp *intel_dp, > return 0; > } > > -static void intel_dp_schedule_fallback_link_training(struct > intel_atomic_state *state, > +static bool intel_dp_schedule_fallback_link_training(struct > intel_atomic_state *state, > struct intel_dp *intel_dp, > const struct > intel_crtc_state *crtc_state) > { > @@ -1195,7 +1193,7 @@ static void > intel_dp_schedule_fallback_link_training(struct intel_atomic_state * > > if (!intel_digital_port_connected(&dp_to_dig_port(intel_dp)->base)) { > lt_dbg(intel_dp, DP_PHY_DPRX, "Link Training failed on > disconnected sink.\n"); > - return; > + return true; > } > > if (intel_dp->hobl_active) { > @@ -1203,11 +1201,13 @@ static void > intel_dp_schedule_fallback_link_training(struct intel_atomic_state * > "Link Training failed with HOBL active, not enabling it > from now on\n"); > intel_dp->hobl_failed = true; > } else if (intel_dp_get_link_train_fallback_values(intel_dp, > crtc_state)) { > - return; > + return false; > } > > /* Schedule a Hotplug Uevent to userspace to start modeset */ > intel_dp_queue_modeset_retry_for_link(state, encoder, crtc_state); > + > + return true; > } > > /* Perform the link training on all LTTPRs and the DPRX on a link. */ > @@ -1518,7 +1518,15 @@ void intel_dp_start_link_train(struct > intel_atomic_state *state, > return; > } > > - intel_dp_schedule_fallback_link_training(state, intel_dp, crtc_state); > + if (intel_dp_schedule_fallback_link_training(state, intel_dp, > crtc_state)) > + return; > + > + intel_dp->link.retrain_disabled = true; > + > + if (!passed) > + lt_err(intel_dp, DP_PHY_DPRX, "Can't reduce link training > parameters after failure\n"); > + else > + lt_dbg(intel_dp, DP_PHY_DPRX, "Can't reduce link training > parameters after forced failure\n");
The forced failure stuff is in later patch, is it not? > } > > void intel_dp_128b132b_sdp_crc16(struct intel_dp *intel_dp, > -- > 2.43.3 -- Ville Syrjälä Intel
