On Tue, Mar 04, 2025 at 07:56:28PM +0200, Jani Nikula wrote:
> On Tue, 04 Mar 2025, Imre Deak <[email protected]> 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 <[email protected]>
> > ---
> > .../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.
Yes, it's used in the sense that the link is active. I guess it could
be renamed to link_active accordingly (can follow up with that).
>
> > @@ -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.
Agreed, can follow up with this separately.
> 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.
Ok, will add a macro for it.
> Regardless,
>
> Reviewed-by: Jani Nikula <[email protected]>
>
> > + 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
