On Tue, 04 Mar 2025, Imre Deak <imre.deak@xxxxxxxxx> wrote:
> After link training - both in case of a passing and failing LT result -
> a work is scheduled to check the link state. This check should take
> place after the link training is completed by disabling the link
> training pattern and setting intel_dp::link_trained=true. Atm, the work
> is scheduled before these steps, which may result in checking the link
> state too early (and thus not retraining the link as expected).
>
> Fix the above by scheduling the link check work after link training is
> complete.
>
> Signed-off-by: Imre Deak <imre.deak@xxxxxxxxx>
> ---
> .../gpu/drm/i915/display/intel_dp_link_training.c | 13 +++++++++----
> 1 file changed, 9 insertions(+), 4 deletions(-)
>
> 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 3906c11acc968..c1be073b9fc48 100644
> --- a/drivers/gpu/drm/i915/display/intel_dp_link_training.c
> +++ b/drivers/gpu/drm/i915/display/intel_dp_link_training.c
> @@ -1110,6 +1110,7 @@ intel_dp_128b132b_intra_hop(struct intel_dp *intel_dp,
> void intel_dp_stop_link_train(struct intel_dp *intel_dp,
> const struct intel_crtc_state *crtc_state)
> {
> + struct intel_display *display = to_intel_display(intel_dp);
> struct intel_encoder *encoder = &dp_to_dig_port(intel_dp)->base;
>
> intel_dp->link_trained = true;
Side note, it's a bit misleading that we set this even if link training
failed... but we probably depend on it.
> @@ -1124,6 +1125,13 @@ void intel_dp_stop_link_train(struct intel_dp *intel_dp,
> }
>
> intel_hpd_unblock(encoder);
> +
> + if (!display->hotplug.ignore_long_hpd &&
We already poke at this directly elsewhere in the file, but I'm not a
fan of doing so. We should have a function and use that. The fact that
we can do anything doesn't mean we should.
I guess that's for another patch, another time.
> + intel_dp->link.seq_train_failures < 2) {
It's not great that the magic 2 is duplicated. It was fine in one place.
Regardless,
Reviewed-by: Jani Nikula <jani.nikula@xxxxxxxxx>
> + int delay_ms = intel_dp->link.seq_train_failures ? 0 : 2000;
> +
> + intel_encoder_link_check_queue_work(encoder, delay_ms);
> + }
> }
>
> static bool
> @@ -1628,7 +1636,6 @@ void intel_dp_start_link_train(struct intel_atomic_state *state,
> lt_dbg(intel_dp, DP_PHY_DPRX, "Forcing link training failure\n");
> } else if (passed) {
> intel_dp->link.seq_train_failures = 0;
> - intel_encoder_link_check_queue_work(encoder, 2000);
> return;
> }
>
> @@ -1651,10 +1658,8 @@ void intel_dp_start_link_train(struct intel_atomic_state *state,
> return;
> }
>
> - if (intel_dp->link.seq_train_failures < 2) {
> - intel_encoder_link_check_queue_work(encoder, 0);
> + if (intel_dp->link.seq_train_failures < 2)
> return;
> - }
>
> if (intel_dp_schedule_fallback_link_training(state, intel_dp, crtc_state))
> return;
--
Jani Nikula, Intel
