Re: [PATCH] drm/i915: Check DP link status on long hpd too

From: Daniel Vetter <daniel@ffwll.ch>
To: Jani Nikula <jani.nikula@linux.intel.com>
Cc: Dave Airlie <airlied@redhat.com>,
	intel-gfx@lists.freedesktop.org, stable@vger.kernel.org
Subject: Re: [PATCH] drm/i915: Check DP link status on long hpd too
Date: Wed, 26 Aug 2015 11:04:27 +0200	[thread overview]
Message-ID: <20150826090427.GM20434@phenom.ffwll.local> (raw)
In-Reply-To: <87lhd5b0vn.fsf@intel.com>

On Fri, Aug 21, 2015 at 09:40:12AM +0300, Jani Nikula wrote:
> On Thu, 20 Aug 2015, ville.syrjala@linux.intel.com wrote:
> > From: Ville Syrjälä <ville.syrjala@linux.intel.com>
> >
> > We are no longer checkling the DP link status on long hpd. We used to do
> > that from the .hot_plug() handler, but it was removed when MST got
> > introduced.
> >
> > If there's no userspace we now fail to retrain the link if the sink
> > power is toggled (or cable yanked and replugged), meaning the user is
> > left staring at a blank screen. With the retraining put back that should
> > be fixed.
> >
> > Also remove the leftover comment that referred to the old retraining
> > from .hot_plug().
> >
> > Fixes a regression introduced in:
> > commit 0e32b39ceed665bfa4a77a4bc307b6652b991632
> > Author: Dave Airlie <airlied@redhat.com>
> > Date:   Fri May 2 14:02:48 2014 +1000
> >
> >     drm/i915: add DP 1.2 MST support (v0.7)
> >
> > Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=89453
> 
> Tested-by: Palmer Dabbelt <palmer@dabbelt.com>

Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>

> 
> > Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=91407
> > Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=89461
> > Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=89594
> > Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=85641
> > Cc: Dave Airlie <airlied@redhat.com>
> > Cc: stable@vger.kernel.org
> > Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
> > ---
> >  drivers/gpu/drm/i915/intel_dp.c | 11 +++++------
> >  1 file changed, 5 insertions(+), 6 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
> > index d32ce48..b014158 100644
> > --- a/drivers/gpu/drm/i915/intel_dp.c
> > +++ b/drivers/gpu/drm/i915/intel_dp.c
> > @@ -5024,9 +5024,12 @@ intel_dp_hpd_pulse(struct intel_digital_port *intel_dig_port, bool long_hpd)
> >  
> >  		intel_dp_probe_oui(intel_dp);
> >  
> > -		if (!intel_dp_probe_mst(intel_dp))
> > +		if (!intel_dp_probe_mst(intel_dp)) {
> > +			drm_modeset_lock(&dev->mode_config.connection_mutex, NULL);
> > +			intel_dp_check_link_status(intel_dp);
> > +			drm_modeset_unlock(&dev->mode_config.connection_mutex);
> >  			goto mst_fail;
> > -
> > +		}
> >  	} else {
> >  		if (intel_dp->is_mst) {
> >  			if (intel_dp_check_mst_status(intel_dp) == -EINVAL)
> > @@ -5034,10 +5037,6 @@ intel_dp_hpd_pulse(struct intel_digital_port *intel_dig_port, bool long_hpd)
> >  		}
> >  
> >  		if (!intel_dp->is_mst) {
> > -			/*
> > -			 * we'll check the link status via the normal hot plug path later -
> > -			 * but for short hpds we should check it now
> > -			 */
> >  			drm_modeset_lock(&dev->mode_config.connection_mutex, NULL);
> >  			intel_dp_check_link_status(intel_dp);
> >  			drm_modeset_unlock(&dev->mode_config.connection_mutex);
> > -- 
> > 2.4.6
> >
> > _______________________________________________
> > Intel-gfx mailing list
> > Intel-gfx@lists.freedesktop.org
> > http://lists.freedesktop.org/mailman/listinfo/intel-gfx
> 
> -- 
> Jani Nikula, Intel Open Source Technology Center
> _______________________________________________
> Intel-gfx mailing list
> Intel-gfx@lists.freedesktop.org
> http://lists.freedesktop.org/mailman/listinfo/intel-gfx

-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch
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