From: Manasi Navare <manasi.d.navare@intel.com> To: ville.syrjala@linux.intel.com Cc: intel-gfx@lists.freedesktop.org, Palmer Dabbelt <palmer@dabbelt.com>, stable@vger.kernel.org Subject: Re: [Intel-gfx] [PATCH] drm/i915: Perform link quality check unconditionally during long pulse Date: Thu, 16 Feb 2017 09:07:53 -0800 [thread overview] Message-ID: <20170216170753.GA27437@intel.com> (raw) In-Reply-To: <20170216153007.14868-1-ville.syrjala@linux.intel.com> On Thu, Feb 16, 2017 at 05:30:07PM +0200, ville.syrjala@linux.intel.com wrote: > From: Ville Syrj�l� <ville.syrjala@linux.intel.com> > > Apparently some DP sinks are a little nuts and cause HPD to drop > intermittently during modesets. This happens eg. on an ASUS PB287Q. > In oder to recover from this we can't really use the previous > connector status to determine if the link needs retraining, so let's > just ignore that piece of information and do the retrain > unconditionally. We do of course still check whether the link is > supposed to be running or not. > > Cc: stable@vger.kernel.org > Cc: Palmer Dabbelt <palmer@dabbelt.com> > Reported-by: Palmer Dabbelt <palmer@dabbelt.com> > References: https://lists.freedesktop.org/archives/intel-gfx/2017-February/119779.html > Signed-off-by: Ville Syrj�l� <ville.syrjala@linux.intel.com> > --- > drivers/gpu/drm/i915/intel_dp.c | 15 +++++++++++---- > 1 file changed, 11 insertions(+), 4 deletions(-) > > diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c > index 024798a9c016..37a746f7fbc3 100644 > --- a/drivers/gpu/drm/i915/intel_dp.c > +++ b/drivers/gpu/drm/i915/intel_dp.c > @@ -4648,11 +4648,18 @@ intel_dp_long_pulse(struct intel_connector *intel_connector) > */ > status = connector_status_disconnected; > goto out; > - } else if (connector->status == connector_status_connected) { > + } else { > /* > - * If display was connected already and is still connected > - * check links status, there has been known issues of > - * link loss triggerring long pulse!!!! > + * 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 apparely > + * 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. > */ > drm_modeset_lock(&dev->mode_config.connection_mutex, NULL); > intel_dp_check_link_status(intel_dp); > -- So here we basically just ignore the connector status and retrain irrespectively. But that means even if we have newer values now for max link rate/lane count from DPCD, during this retrain we are just using the stale value of intel_dp->link_rate and intel_dp->lane_count. I think intel_dp->link_rate and lane count values should be set to 0 on HPD pulse, they would be set only during a modeset. Regards Manasi > 2.10.2 > > _______________________________________________ > Intel-gfx mailing list > Intel-gfx@lists.freedesktop.org > https://lists.freedesktop.org/mailman/listinfo/intel-gfx
WARNING: multiple messages have this Message-ID (diff)
From: Manasi Navare <manasi.d.navare@intel.com> To: ville.syrjala@linux.intel.com Cc: intel-gfx@lists.freedesktop.org, Palmer Dabbelt <palmer@dabbelt.com>, stable@vger.kernel.org Subject: Re: [Intel-gfx] [PATCH] drm/i915: Perform link quality check unconditionally during long pulse Date: Thu, 16 Feb 2017 09:07:53 -0800 [thread overview] Message-ID: <20170216170753.GA27437@intel.com> (raw) In-Reply-To: <20170216153007.14868-1-ville.syrjala@linux.intel.com> On Thu, Feb 16, 2017 at 05:30:07PM +0200, ville.syrjala@linux.intel.com wrote: > From: Ville Syrjälä <ville.syrjala@linux.intel.com> > > Apparently some DP sinks are a little nuts and cause HPD to drop > intermittently during modesets. This happens eg. on an ASUS PB287Q. > In oder to recover from this we can't really use the previous > connector status to determine if the link needs retraining, so let's > just ignore that piece of information and do the retrain > unconditionally. We do of course still check whether the link is > supposed to be running or not. > > Cc: stable@vger.kernel.org > Cc: Palmer Dabbelt <palmer@dabbelt.com> > Reported-by: Palmer Dabbelt <palmer@dabbelt.com> > References: https://lists.freedesktop.org/archives/intel-gfx/2017-February/119779.html > Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com> > --- > drivers/gpu/drm/i915/intel_dp.c | 15 +++++++++++---- > 1 file changed, 11 insertions(+), 4 deletions(-) > > diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c > index 024798a9c016..37a746f7fbc3 100644 > --- a/drivers/gpu/drm/i915/intel_dp.c > +++ b/drivers/gpu/drm/i915/intel_dp.c > @@ -4648,11 +4648,18 @@ intel_dp_long_pulse(struct intel_connector *intel_connector) > */ > status = connector_status_disconnected; > goto out; > - } else if (connector->status == connector_status_connected) { > + } else { > /* > - * If display was connected already and is still connected > - * check links status, there has been known issues of > - * link loss triggerring long pulse!!!! > + * 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 apparely > + * 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. > */ > drm_modeset_lock(&dev->mode_config.connection_mutex, NULL); > intel_dp_check_link_status(intel_dp); > -- So here we basically just ignore the connector status and retrain irrespectively. But that means even if we have newer values now for max link rate/lane count from DPCD, during this retrain we are just using the stale value of intel_dp->link_rate and intel_dp->lane_count. I think intel_dp->link_rate and lane count values should be set to 0 on HPD pulse, they would be set only during a modeset. Regards Manasi > 2.10.2 > > _______________________________________________ > Intel-gfx mailing list > Intel-gfx@lists.freedesktop.org > https://lists.freedesktop.org/mailman/listinfo/intel-gfx
next prev parent reply other threads:[~2017-02-16 17:08 UTC|newest] Thread overview: 41+ messages / expand[flat|nested] mbox.gz Atom feed top 2017-02-10 22:44 [PATCH] drm/i915: Fix DisplayPort Hotplug Palmer Dabbelt 2017-02-14 8:22 ` ✗ Fi.CI.BAT: warning for " Patchwork 2017-02-14 8:54 ` Saarinen, Jani 2017-02-14 15:01 ` [PATCH] " Ville Syrjälä 2017-02-14 18:48 ` Palmer Dabbelt 2017-02-14 19:00 ` Ville Syrjälä 2017-02-16 2:58 ` Palmer Dabbelt 2017-02-16 15:26 ` Ville Syrjälä 2017-02-16 15:30 ` [PATCH] drm/i915: Perform link quality check unconditionally during long pulse ville.syrjala 2017-02-16 15:30 ` ville.syrjala 2017-02-16 15:39 ` Palmer Dabbelt 2017-02-16 15:39 ` Palmer Dabbelt 2017-02-16 15:49 ` Ville Syrjälä 2017-02-16 15:49 ` Ville Syrjälä 2017-02-16 17:07 ` Manasi Navare [this message] 2017-02-16 17:07 ` [Intel-gfx] " Manasi Navare 2017-02-16 17:18 ` Ville Syrjälä 2017-02-16 17:18 ` Ville Syrjälä 2017-02-16 17:24 ` [Intel-gfx] " Manasi Navare 2017-02-16 17:24 ` Manasi Navare 2017-02-16 17:46 ` [Intel-gfx] " Ville Syrjälä 2017-02-16 17:46 ` Ville Syrjälä 2017-02-23 4:00 ` [Intel-gfx] " Palmer Dabbelt 2017-02-23 4:00 ` Palmer Dabbelt 2017-02-23 9:22 ` [Intel-gfx] " Ville Syrjälä 2017-02-23 9:22 ` Ville Syrjälä 2017-03-13 20:53 ` [PATCH v2] " ville.syrjala 2017-03-13 20:53 ` ville.syrjala 2017-03-13 21:20 ` [Intel-gfx] " Chris Wilson 2017-03-13 21:20 ` Chris Wilson 2017-03-13 23:09 ` Manasi Navare 2017-03-13 23:09 ` Manasi Navare 2017-03-14 10:15 ` Ville Syrjälä 2017-03-14 10:15 ` Ville Syrjälä 2017-04-12 19:30 ` [PATCH v3] " ville.syrjala 2017-04-12 19:30 ` ville.syrjala 2017-04-13 12:27 ` Ville Syrjälä 2017-04-13 12:27 ` Ville Syrjälä 2017-02-16 19:52 ` ✓ Fi.CI.BAT: success for drm/i915: Fix DisplayPort Hotplug (rev2) Patchwork 2017-03-13 21:47 ` ✓ Fi.CI.BAT: success for drm/i915: Fix DisplayPort Hotplug (rev3) Patchwork 2017-04-12 19:47 ` ✓ Fi.CI.BAT: success for drm/i915: Fix DisplayPort Hotplug (rev4) Patchwork
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