[Intel-gfx] [PATCH v2 3/5] drm/i915: Move SST DP link retraining into the ->post_hotplug() hook
Manasi Navare
manasi.d.navare at intel.com
Mon Mar 5 23:41:44 UTC 2018
On Wed, Feb 28, 2018 at 03:10:24PM -0500, Lyude Paul wrote:
> On Wed, 2018-02-28 at 11:57 -0800, Manasi Navare wrote:
> > On Wed, Feb 28, 2018 at 02:41:06PM -0500, Lyude Paul wrote:
> > > On Wed, 2018-02-28 at 11:27 -0800, Manasi Navare wrote:
> > > > On Wed, Feb 28, 2018 at 02:07:34PM -0500, Lyude Paul wrote:
> > > > >
> > > > > On Tue, 2018-02-27 at 23:17 -0800, Manasi Navare wrote:
> > > > > > Ville, thanks for the patch and
> > > > > > Sorry for not being able to review this earlier.
> > > > > > Please find some comments below:
> > > > > >
> > > > > > On Wed, Jan 31, 2018 at 03:27:10PM +0200, Ville Syrjälä wrote:
> > > > > > > On Tue, Jan 30, 2018 at 06:16:59PM -0500, Lyude Paul wrote:
> > > > > > > > On Wed, 2018-01-17 at 21:21 +0200, Ville Syrjala wrote:
> > > > > > > > > From: Ville Syrjälä <ville.syrjala at linux.intel.com>
> > > > > > > > >
> > > > > > > > > Doing link retraining from the short pulse handler is
> > > > > > > > > problematic
> > > > > > > > > since
> > > > > > > > > that might introduce deadlocks with MST sideband processing.
> > > > > > > > > Currently
> > > > > > > > > we don't retrain MST links from this code, but we want to
> > > > > > > > > change
> > > > > > > > > that.
> > > > > > > > > So better to move the entire thing to the hotplug work. We can
> > > > > > > > > utilize
> > > > > > > > > the new encoder->hotplug() hook for this.
> > > > > > > > >
> > > > > > > > > The only thing we leave in the short pulse handler is the link
> > > > > > > > > status
> > > > > > > > > check. That one still depends on the link parameters stored
> > > > > > > > > under
> > > > > > > > > intel_dp, so no locking around that but races should be mostly
> > > > > > > > > harmless
> > > > > > > > > as the actual retraining code will recheck the link state if
> > > > > > > > > we
> > > > > > > > > end up there by mistake.
> > > > > > > > >
> > > > > > > > > v2: Rebase due to ->post_hotplug() now being just ->hotplug()
> > > > > > > > > Check the connector type to figure out if we should do
> > > > > > > > > the HDMI thing or the DP think for DDI
> > > > > > > > >
> > > > > > > > > Cc: Manasi Navare <manasi.d.navare at intel.com>
> > > > > > > > > Cc: Maarten Lankhorst <maarten.lankhorst at linux.intel.com>
> > > > > > > > > Signed-off-by: Ville Syrjälä <ville.syrjala at linux.intel.com>
> > > > > > > > > ---
> > > > > > > > > drivers/gpu/drm/i915/intel_ddi.c | 10 +-
> > > > > > > > > drivers/gpu/drm/i915/intel_dp.c | 196
> > > > > > > > > ++++++++++++++++++++++--
> > > > > > > > > ----
> > > > > > > > > --------
> > > > > > > > > ---
> > > > > > > > > drivers/gpu/drm/i915/intel_drv.h | 2 +
> > > > > > > > > 3 files changed, 120 insertions(+), 88 deletions(-)
> > > > > > > > >
> > > > > > > > > diff --git a/drivers/gpu/drm/i915/intel_ddi.c
> > > > > > > > > b/drivers/gpu/drm/i915/intel_ddi.c
> > > > > > > > > index 25793bdc692f..5f3d58f1ae6e 100644
> > > > > > > > > --- a/drivers/gpu/drm/i915/intel_ddi.c
> > > > > > > > > +++ b/drivers/gpu/drm/i915/intel_ddi.c
> > > > > > > > > @@ -2880,7 +2880,10 @@ static bool intel_ddi_hotplug(struct
> > > > > > > > > intel_encoder
> > > > > > > > > *encoder,
> > > > > > > > > drm_modeset_acquire_init(&ctx, 0);
> > > > > > > > >
> > > > > > > > > for (;;) {
> > > > > > > > > - ret = intel_hdmi_reset_link(encoder, &ctx);
> > > > > > > > > + if (connector->base.connector_type ==
> > > > > > > > > DRM_MODE_CONNECTOR_HDMIA)
> > > > > > > > > + ret = intel_hdmi_reset_link(encoder,
> > > > > > > > > &ctx);
> > > > > > > > > + else
> > > > > > > > > + ret = intel_dp_retrain_link(encoder,
> > > > > > > > > &ctx);
> > > > > > > > >
> > > > > > > > > if (ret == -EDEADLK) {
> > > > > > > > > drm_modeset_backoff(&ctx);
> > > > > > > > > @@ -3007,10 +3010,7 @@ void intel_ddi_init(struct
> > > > > > > > > drm_i915_private
> > > > > > > > > *dev_priv,
> > > > > > > > > enum port port)
> > > > > > > > > drm_encoder_init(&dev_priv->drm, encoder,
> > > > > > > > > &intel_ddi_funcs,
> > > > > > > > > DRM_MODE_ENCODER_TMDS, "DDI %c",
> > > > > > > > > port_name(port));
> > > > > > > > >
> > > > > > > > > - if (init_hdmi)
> > > > > > > > > - intel_encoder->hotplug = intel_ddi_hotplug;
> > > > > > > > > - else
> > > > > > > > > - intel_encoder->hotplug =
> > > > > > > > > intel_encoder_hotplug;
> > > > > > > > > + intel_encoder->hotplug = intel_ddi_hotplug;
> > > > > > > > > intel_encoder->compute_output_type =
> > > > > > > > > intel_ddi_compute_output_type;
> > > > > > > > > intel_encoder->compute_config =
> > > > > > > > > intel_ddi_compute_config;
> > > > > > > > > intel_encoder->enable = intel_enable_ddi;
> > > > > > > > > diff --git a/drivers/gpu/drm/i915/intel_dp.c
> > > > > > > > > b/drivers/gpu/drm/i915/intel_dp.c
> > > > > > > > > index 6bbf14410c2a..152016e09a11 100644
> > > > > > > > > --- a/drivers/gpu/drm/i915/intel_dp.c
> > > > > > > > > +++ b/drivers/gpu/drm/i915/intel_dp.c
> > > > > > > > > @@ -4275,12 +4275,83 @@ intel_dp_check_mst_status(struct
> > > > > > > > > intel_dp
> > > > > > > > > *intel_dp)
> > > > > > > > > return -EINVAL;
> > > > > > > > > }
> > > > > > > > >
> > > > > > > > > -static void
> > > > > > > > > -intel_dp_retrain_link(struct intel_dp *intel_dp)
> > > > > > > > > +static bool
> > > > > > > > > +intel_dp_needs_link_retrain(struct intel_dp *intel_dp)
> > > > > > > > > +{
> > > > > > > > > + u8 link_status[DP_LINK_STATUS_SIZE];
> > > > > > > > > +
> > > > > > > > > + if (!intel_dp_get_link_status(intel_dp, link_status))
> > > > > > > > > {
> > > > > > > > > + DRM_ERROR("Failed to get link status\n");
> > > > > > > > > + return false;
> > > > > > > > > + }
> > > > > > > > > +
> > > > > > > > > + /*
> > > > > > > > > + * Validate the cached values of intel_dp->link_rate
> > > > > > > > > and
> > > > > > > > > + * intel_dp->lane_count before attempting to retrain.
> > > > > > > > > + */
> > > > > > > > > + if (!intel_dp_link_params_valid(intel_dp, intel_dp-
> > > > > > > > > > link_rate,
> > > > > > > > >
> > > > > > > > > + intel_dp-
> > > > > > > > > >lane_count))
> > > > > > > > > + return false;
> > > > > > > > > +
> > > > > > > > > + /* Retrain if Channel EQ or CR not ok */
> > > > > > > > > + return !drm_dp_channel_eq_ok(link_status, intel_dp-
> > > > > > > > > > lane_count);
> > > > > > > > >
> > > > > > > > > +}
> > > > > > > > > +
> > > > > > > > > +/*
> > > > > > > > > + * If display is now connected check links status,
> > > > > > > > > + * there has been known issues of link loss triggering
> > > > > > > > > + * long pulse.
> > > > > > > > > + *
> > > > > > > > > + * Some sinks (eg. ASUS PB287Q) seem to perform some
> > > > > > > > > + * weird HPD ping pong during modesets. So we can apparently
> > > > > > > > > + * end up with HPD going low during a modeset, and then
> > > > > > > > > + * going back up soon after. And once that happens we must
> > > > > > > > > + * retrain the link to get a picture. That's in case no
> > > > > > > > > + * userspace component reacted to intermittent HPD dip.
> > > > > > > > > + */
> > > > > > > > > +int intel_dp_retrain_link(struct intel_encoder *encoder,
> > > > > > > > > + struct drm_modeset_acquire_ctx
> > > > > > > > > *ctx)
> > > > > > > > > {
> > > > > > > > > - 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);
> > > > > > > > >
> > > > > > > > > + struct intel_dp *intel_dp = enc_to_intel_dp(&encoder-
> > > > > > > > > > base);
> > > > > > > > >
> > > > > > > > > + struct intel_connector *connector = intel_dp-
> > > > > > > > > > attached_connector;
> > > > > > > > >
> > > > > > > > > + struct drm_connector_state *conn_state;
> > > > > > > > > + struct intel_crtc_state *crtc_state;
> > > > > > > > > + struct intel_crtc *crtc;
> > > > > > > > > + int ret;
> > > > > > > > > +
> > > > > > > > > + /* FIXME handle the MST connectors as well */
> > > > > > > > > +
> > > > > > > > > + if (!connector || connector->base.status !=
> > > > > > > > > connector_status_connected)
> > > > > > > > > + return 0;
> > > > > > > > > +
> > > > > > > > > + ret = drm_modeset_lock(&dev_priv-
> > > > > > > > > > drm.mode_config.connection_mutex,
> > > > > > > > >
> > > > > > > > > ctx);
> > > > > > > > > + if (ret)
> > > > > > > > > + return ret;
> > > > > > > > > +
> > > > > > > > > + conn_state = connector->base.state;
> > > > > > > > > +
> > > > > > > > > + crtc = to_intel_crtc(conn_state->crtc);
> > > > > > > > > + if (!crtc)
> > > > > > > > > + return 0;
> > > > > > > > > +
> > > > > > > > > + ret = drm_modeset_lock(&crtc->base.mutex, ctx);
> > > > > > > > > + if (ret)
> > > > > > > > > + return ret;
> > > > > > > > > +
> > > > > > > > > + crtc_state = to_intel_crtc_state(crtc->base.state);
> > > > > > > > > +
> > > > > > > > > + WARN_ON(!intel_crtc_has_dp_encoder(crtc_state));
> > > > > > > > > +
> > > > > > > > > + if (!crtc_state->base.active)
> > > > > > > > > + return 0;
> > > > > > > > > +
> > > > > > > > > + if (conn_state->commit &&
> > > > > > > > > + !try_wait_for_completion(&conn_state->commit-
> > > > > > > > > > hw_done))
> > > > > > > > >
> > > > > > > > > + return 0;
> > > > > > > > > +
> > > > > > > > > + if (!intel_dp_needs_link_retrain(intel_dp))
> > > > > > > > > + return 0;
> > > > > > > >
> > > > > > > > NAK, this definitely won't work for implementing MST retraining.
> > > > > > > > There's
> > > > > > > > some
> > > > > > > > pretty huge differences with how retraining needs to be handled
> > > > > > > > on
> > > > > > > > SST
> > > > > > > > vs. MST.
> > > > > > > > An example with some normal SST sink vs. what happens on my
> > > > > > > > caldigit
> > > > > > > > TS3
> > > > > > > >
> > > > > > > > SST:
> > > > > > > > 1. commit modeset, everything is OK
> > > > > > > > 2. something happens, sink sends shortpulse and changes link
> > > > > > > > status
> > > > > > > > registers
> > > > > > > > in dpcd
> > > > > > > > 3. Source receives short pulse, tries retraining five times
> > > > > > > > 4. if this succeeds:
> > > > > > > > 5. we're done here
> > > > > > > > 6. if this fails:
> > > > > > > > 7. mark link status as bad
> > > > > > > > 8. get fallback parameters
> > > > > > > > 9. hotplug event
> > > > > > > >
> > > > > > > > MST (i915 doesn't do this yet, but this is generally how it
> > > > > > > > needs to
> > > > > > > > be
> > > > > > > > handled):
> > > > > > > > 1. commit modeset, everything is OK
> > > > > > > > 2. something happens (in my case, the MST hub discovers it
> > > > > > > > had
> > > > > > > > the
> > > > > > > > wrong max
> > > > > > > > link rate/lane count), sink sends ESI indicating channel EQ
> > > > > > > > has
> > > > > > > > failed
> > > > > > > > 3. retraining commences with five retries.
> > > > > > > > 4. if this succeeds:
> > > > > > > > 5. continue
> > > > > > > > 6. if this fails (I actually haven't seen this once yet)
> > > > > > > > 7. mark link status as bad on all downstream connectors
> > > > > > > > 8. get fallback parameters
> > > > > > > > 9. hotplug event
> > > > > > > > 10. the retrain didn't actually work (despite what the SST
> > > > > > > > link
> > > > > > > > status
> > > > > > > > registers told us). go back to step 3 five more times
> > > > > > > > 11. if this fails:
> > > > > > > > 12. mark link status as bad on all downstream connectors
> > > > > > > > 13. get fallback parameters
> > > > > > > > 14. hotplug event
> > > > > > > >
> > > > > > > > simply put: we really should keep the "do we need to retrain?"
> > > > > > > > logic
> > > > > > > > out
> > > > > > > > of the
> > > > > > > > actual retraining helpers so that SST/MST codepaths can do their
> > > > > > > > own
> > > > > > > > checks to
> > > > > > > > figure this out.
> > > > > > >
> > > > > > > No, we need it since we want to check it *after* any modeset has
> > > > > > > finished. With MST I think what we'll want to do is find all the
> > > > > > > pipes
> > > > > > > affected by the link failure, lock them, and wait until they're
> > > > > > > done
> > > > > > > with their modesets, then we check the link state. If it's bad we
> > > > > > > proceed to retrain the link.
> > > > > > >
> > > > > > > So basically just walking over the MST encoders in addition to the
> > > > > > > SST encoder, and repeating most of the steps in this code for
> > > > > > > each.
> > > > > > > Hence the the MST FIXME I left in there ;)
> > > > > > >
> > > > > >
> > > > > > Lyude,
> > > > > >
> > > > > > I agree with Ville here, can we add the MST retrain required check
> > > > > > from
> > > > > > within the intel_dp_retrain_link()? So for now the FIXME should be
> > > > > > left
> > > > > > there
> > > > > > and MST retraining check can be added from your patches.
> > > > > >
> > > > > > Manasi
> > > > >
> > > > > Yep! Sorry I probably should have reiterated this part over email
> > > > > since I
> > > > > only
> > > > > mentioned it to ville directly: this part should definitely work fine,
> > > > > and
> > > > > intel_dp_retrain_link() is actually where we handle MST retraining in
> > > > > the
> > > > > latest version of the retraining series:
> > > > >
> > > > > jfyi, you can find that here:
> > > > > https://github.com/Lyude/linux/tree/wip/i915-mst-fallback-a4
> > > > > It's almost ready for the ML, just want to get the other patches this
> > > > > is
> > > > > going
> > > > > to rely on in first and fix some small concerns I've got about that
> > > > > series'
> > > > > current implementation of handling modesets after a failed retrain
> > > > > sequence
> > > > > >
> > > >
> > > > Great!
> > > > After the failed retrain sequence, it will keep on retrying until has
> > > > tried
> > > > all
> > > > the link rate/lane count combinations until RBR 1 lane and then fail
> > > > with a
> > > > ERROR message.
> > > > What was the concern on the current implementation of modeste after
> > > > failed
> > > > retrain?
> > >
> > > I actually take that back. Was worried that not freeing existing VCPI
> > > allocations during the first atomic check phase for the first modeset
> > > after a
> > > retrain failure might cause atomic checks to fail from not having enough
> > > VCPI
> > > space, but then I realized that wouldn't matter since if we're not able to
> > > fit
> > > one display into the VCPI with a reduced pbn_div, that just means fitting
> > > both
> > > displays with a reduced pbn_div would also be impossible :P.
> > >
> >
> > But then in that case, in oredr to retry at lower link rates, both these
> > monitors will
> > have to drop to the next lower resolutions to fit the reduced pbn_div.
>
> Yep, that's the idea! In which case the atomic check should fail, which should
> cause userspace to try at a reduced resolution or take some other reparative
> action
> >
> > Manasi
> >
> > > >
> > > > Manasi
> > > >
> > > > > > > >
> > > > > > > > >
> > > > > > > > > /* Suppress underruns caused by re-training */
> > > > > > > > > intel_set_cpu_fifo_underrun_reporting(dev_priv, crtc-
> > > > > > > > > > pipe,
> > > > > > > > >
> > > > > > > > > false);
> > > > > > > > > @@ -4298,51 +4369,49 @@ intel_dp_retrain_link(struct intel_dp
> > > > > > > > > *intel_dp)
> > > > > > > > > if (crtc->config->has_pch_encoder)
> > > > > > > > > intel_set_pch_fifo_underrun_reporting(dev_pri
> > > > > > > > > v,
> > > > > > > > > intel_c
> > > > > > > > > rtc_
> > > > > > > > > pch_
> > > > > > > > > transcod
> > > > > > > > > er(crtc), true);
> > > > > > > > > +
> > > > > > > > > + return 0;
> > > > > > > > > }
> > > > > > > > >
> > > > > > > > > -static void
> > > > > > > > > -intel_dp_check_link_status(struct intel_dp *intel_dp)
> > > > > > > > > +/*
> > > > > > > > > + * If display is now connected check links status,
> > > > > > > > > + * there has been known issues of link loss triggering
> > > > > > > > > + * long pulse.
> > > > > > > > > + *
> > > > > > > > > + * Some sinks (eg. ASUS PB287Q) seem to perform some
> > > > > > > > > + * weird HPD ping pong during modesets. So we can apparently
> > > > > > > > > + * end up with HPD going low during a modeset, and then
> > > > > > > > > + * going back up soon after. And once that happens we must
> > > > > > > > > + * retrain the link to get a picture. That's in case no
> > > > > > > > > + * userspace component reacted to intermittent HPD dip.
> > > > > > > > > + */
> > > > > > > > > +static bool intel_dp_hotplug(struct intel_encoder *encoder,
> > > > > > > > > + struct intel_connector
> > > > > > > > > *connector)
> > > > > > > > > {
> > > > > > > > > - struct drm_i915_private *dev_priv =
> > > > > > > > > to_i915(intel_dp_to_dev(intel_dp));
> > > > > > > > > - struct intel_encoder *intel_encoder =
> > > > > > > > > &dp_to_dig_port(intel_dp)-
> > > > > > > > > > base;
> > > > > > > > >
> > > > > > > > > - struct drm_connector_state *conn_state =
> > > > > > > > > - intel_dp->attached_connector->base.state;
> > > > > > > > > - u8 link_status[DP_LINK_STATUS_SIZE];
> > > > > > > > > -
> > > > > > > > > - WARN_ON(!drm_modeset_is_locked(&dev_priv-
> > > > > > > > > > drm.mode_config.connection_mutex));
> > > > > > > > >
> > > > > > > > > -
> > > > > > > > > - if (!intel_dp_get_link_status(intel_dp, link_status))
> > > > > > > > > {
> > > > > > > > > - DRM_ERROR("Failed to get link status\n");
> > > > > > > > > - return;
> > > > > > > > > - }
> > > > > > > > > + struct drm_modeset_acquire_ctx ctx;
> > > > > > > > > + bool changed;
> > > > > > > > > + int ret;
> > > > > > > > >
> > > > > > > > > - if (!conn_state->crtc)
> > > > > > > > > - return;
> > > > > > > > > + changed = intel_encoder_hotplug(encoder, connector);
> > > > > > > > >
> > > > > > > > > - WARN_ON(!drm_modeset_is_locked(&conn_state->crtc-
> > > > > > > > > > mutex));
> > > > > > > > >
> > > > > > > > > + drm_modeset_acquire_init(&ctx, 0);
> > > > > > > > >
> > > > > > > > > - if (!conn_state->crtc->state->active)
> > > > > > > > > - return;
> > > > > > > > > + for (;;) {
> > > > > >
> > > > > > Here if this is getting executed due to hpd ping pong during the
> > > > > > modeset
> > > > > > and that modeset is already happening at a link fallback parameter
> > > > > > then
> > > > > > while we call retrain link, we should also validate the link
> > > > > > parameters
> > > > > > so that it doesnt try to retrain with stale values.
> > > > > >
> > > > > > I think we need to call intel_dp_link_params_valid() before retrain.
I missed that intel_dp_retrain_link() does call intel_dp_link_params_valid() through
intel_dp_needs_retrain(). So ignore my concern above.
With that,
Acked-by: Manasi Navare <manasi.d.navare at intel.com>
Manasi
> > > > > >
> > > > > > > > > + ret = intel_dp_retrain_link(encoder, &ctx);
> > > > > > > > >
> > > > > > > > > - if (conn_state->commit &&
> > > > > > > > > - !try_wait_for_completion(&conn_state->commit-
> > > > > > > > > > hw_done))
> > > > > > > > >
> > > > > > > > > - return;
> > > > > > > > > + if (ret == -EDEADLK) {
> > > > > > > > > + drm_modeset_backoff(&ctx);
> > > > > > > > > + continue;
> > > > > > > > > + }
> > > > > > > > >
> > > > > > > > > - /*
> > > > > > > > > - * Validate the cached values of intel_dp->link_rate
> > > > > > > > > and
> > > > > > > > > - * intel_dp->lane_count before attempting to retrain.
> > > > > > > > > - */
> > > > > > > > > - if (!intel_dp_link_params_valid(intel_dp, intel_dp-
> > > > > > > > > > link_rate,
> > > > > > > > >
> > > > > > > > > - intel_dp-
> > > > > > > > > >lane_count))
> > > > > > > > > - return;
> > > > > > > > > + break;
> > > > > > > > > + }
> > > > > > > > >
> > > > > > > > > - /* Retrain if Channel EQ or CR not ok */
> > > > > > > > > - if (!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);
> > > > > > > > > + drm_modeset_drop_locks(&ctx);
> > > > > > > > > + drm_modeset_acquire_fini(&ctx);
> > > > > > > > > + WARN(ret, "Acquiring modeset locks failed with %i\n",
> > > > > > > > > ret);
> > > > > > > > >
> > > > > > > > > - intel_dp_retrain_link(intel_dp);
> > > > > > > > > - }
> > > > > > > > > + return changed;
> > > > > > > > > }
> > > > > > > > >
> > > > > > > > > /*
> > > > > > > > > @@ -4400,7 +4469,9 @@ intel_dp_short_pulse(struct intel_dp
> > > > > > > > > *intel_dp)
> > > > > > > > > DRM_DEBUG_DRIVER("CP or sink specific
> > > > > > > > > irq
> > > > > > > > > unhandled\n");
> > > > > > > > > }
> > > > > > > > >
> > > > > > > > > - intel_dp_check_link_status(intel_dp);
> > > > > > > > > + /* defer to the hotplug work for link retraining if
> > > > > > > > > needed */
> > > > > > > > > + if (intel_dp_needs_link_retrain(intel_dp))
> > > > > > > > > + return false;
> > > > > > > > >
> > > > > > > > > if (intel_dp->compliance.test_type ==
> > > > > > > > > DP_TEST_LINK_TRAINING)
> > > > > > > > > {
> > > > > > > > > DRM_DEBUG_KMS("Link Training Compliance Test
> > > > > > > > > requested\n");
> > > > > > > > > @@ -4785,20 +4856,6 @@ intel_dp_long_pulse(struct
> > > > > > > > > intel_connector
> > > > > > > > > *connector)
> > > > > > > > > */
> > > > > > > > > status = connector_status_disconnected;
> > > > > > > > > goto out;
> > > > > > > > > - } else {
> > > > > > > > > - /*
> > > > > > > > > - * If display is now connected check links
> > > > > > > > > status,
> > > > > > > > > - * there has been known issues of link loss
> > > > > > > > > triggerring
> > > > > > > > > - * long pulse.
> > > > > > > > > - *
> > > > > > > > > - * Some sinks (eg. ASUS PB287Q) seem to
> > > > > > > > > perform
> > > > > > > > > some
> > > > > > > > > - * weird HPD ping pong during modesets. So we
> > > > > > > > > can
> > > > > > > > > apparently
> > > > > > > > > - * end up with HPD going low during a
> > > > > > > > > modeset,
> > > > > > > > > and
> > > > > > > > > then
> > > > > > > > > - * going back up soon after. And once that
> > > > > > > > > happens we
> > > > > > > > > must
> > > > > > > > > - * retrain the link to get a picture. That's
> > > > > > > > > in
> > > > > > > > > case
> > > > > > > > > no
> > > > > > > > > - * userspace component reacted to
> > > > > > > > > intermittent
> > > > > > > > > HPD
> > > > > > > > > dip.
> > > > > > > > > - */
> > > > > > > > > - intel_dp_check_link_status(intel_dp);
> > > > > > > > > }
> > > > > > > > >
> > > > > > > > > /*
> > > > > > > > > @@ -5340,37 +5397,10 @@ intel_dp_hpd_pulse(struct
> > > > > > > > > intel_digital_port
> > > > > > > > > *intel_dig_port, bool long_hpd)
> > > > > > > > > }
> > > > > > > > >
> > > > > > > > > if (!intel_dp->is_mst) {
> > > > > > > > > - struct drm_modeset_acquire_ctx ctx;
> > > > > > > > > - struct drm_connector *connector = &intel_dp-
> > > > > > > > > > attached_connector->base;
> > > > > > > > >
> > > > > > > > > - struct drm_crtc *crtc;
> > > > > > > > > - int iret;
> > > > > > > > > - bool handled = false;
> > > > > > > > > -
> > > > > > > > > - drm_modeset_acquire_init(&ctx, 0);
> > > > > > > > > -retry:
> > > > > > > > > - iret = drm_modeset_lock(&dev_priv-
> > > > > > > > > > drm.mode_config.connection_mutex, &ctx);
> > > > > > > > >
> > > > > > > > > - if (iret)
> > > > > > > > > - goto err;
> > > > > > > > > -
> > > > > > > > > - crtc = connector->state->crtc;
> > > > > > > > > - if (crtc) {
> > > > > > > > > - iret = drm_modeset_lock(&crtc->mutex,
> > > > > > > > > &ctx);
> > > > > > > > > - if (iret)
> > > > > > > > > - goto err;
> > > > > > > > > - }
> > > > > > > > > + bool handled;
> > > > > > > > >
> > > > > > > > > handled = intel_dp_short_pulse(intel_dp);
> > > > > > > > >
> > > > > > > > > -err:
> > > > > > > > > - if (iret == -EDEADLK) {
> > > > > > > > > - drm_modeset_backoff(&ctx);
> > > > > > > > > - goto retry;
> > > > > > > > > - }
> > > > > > > > > -
> > > > > > > > > - drm_modeset_drop_locks(&ctx);
> > > > > > > > > - drm_modeset_acquire_fini(&ctx);
> > > > > > > > > - WARN(iret, "Acquiring modeset locks failed
> > > > > > > > > with
> > > > > > > > > %i\n", iret);
> > > > > > > > > -
> > > > > > > > > /* Short pulse can signify loss of hdcp
> > > > > > > > > authentication */
> > > > > > > > > intel_hdcp_check_link(intel_dp-
> > > > > > > > > > attached_connector);
> > > > > > > > >
> > > > > > > > >
> > > > > > > > > @@ -6400,7 +6430,7 @@ bool intel_dp_init(struct
> > > > > > > > > drm_i915_private
> > > > > > > > > *dev_priv,
> > > > > > > > > "DP %c", port_name(port)))
> > > > > > > > > goto err_encoder_init;
> > > > > > > > >
> > > > > > > > > - intel_encoder->hotplug = intel_encoder_hotplug;
> > > > > > > > > + intel_encoder->hotplug = intel_dp_hotplug;
> > > > > > > > > intel_encoder->compute_config =
> > > > > > > > > intel_dp_compute_config;
> > > > > > > > > intel_encoder->get_hw_state = intel_dp_get_hw_state;
> > > > > > > > > intel_encoder->get_config = intel_dp_get_config;
> > > > > > > > > diff --git a/drivers/gpu/drm/i915/intel_drv.h
> > > > > > > > > b/drivers/gpu/drm/i915/intel_drv.h
> > > > > > > > > index 5ea1dc3f63bf..ddf28a442cd7 100644
> > > > > > > > > --- a/drivers/gpu/drm/i915/intel_drv.h
> > > > > > > > > +++ b/drivers/gpu/drm/i915/intel_drv.h
> > > > > > > > > @@ -1611,6 +1611,8 @@ int
> > > > > > > > > intel_dp_get_link_train_fallback_values(struct
> > > > > > > > > intel_dp *intel_dp,
> > > > > > > > > int link_rate,
> > > > > > > > > uint8_t
> > > > > > > > > lane_count);
> > > > > > > > > void intel_dp_start_link_train(struct intel_dp *intel_dp);
> > > > > > > > > void intel_dp_stop_link_train(struct intel_dp *intel_dp);
> > > > > > > > > +int intel_dp_retrain_link(struct intel_encoder *encoder,
> > > > > > > > > + struct drm_modeset_acquire_ctx
> > > > > > > > > *ctx);
> > > > > > > > > void intel_dp_sink_dpms(struct intel_dp *intel_dp, int mode);
> > > > > > > > > void intel_dp_encoder_reset(struct drm_encoder *encoder);
> > > > > > > > > void intel_dp_encoder_suspend(struct intel_encoder
> > > > > > > > > *intel_encoder);
> > > > > > >
> > > > > > > --
> > > > > > > Ville Syrjälä
> > > > > > > Intel OTC
> > > > > > > _______________________________________________
> > > > > > > Intel-gfx mailing list
> > > > > > > Intel-gfx at lists.freedesktop.org
> > > > > > > https://lists.freedesktop.org/mailman/listinfo/intel-gfx
> > > > >
> > > > > --
> > > > > Cheers,
> > > > > Lyude Paul
> > >
> > > --
> > > Cheers,
> > > Lyude Paul
> --
> Cheers,
> Lyude Paul
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