Re: [PATCH 07/14] drm/i915: Warn about want_panel_vdd in edp_panel_vdd_off_sync()

["Ville Syrjälä" <ville.syrjala@linux.intel.com>]

On Tue, Aug 19, 2014 at 10:36:52AM +0300, Jani Nikula wrote:
> On Mon, 18 Aug 2014, ville.syrjala@linux.intel.com wrote:
> > From: Ville Syrjälä <ville.syrjala@linux.intel.com>
> >
> > If we force vdd off warn if someone is still using it. With this
> > change the delayed vdd off work needs to check want_panel_vdd
> > itself to make sure it doesn't try to turn vdd off when someone
> > is using it.
> 
> I think this calls for a prep cleanup patch to check and fix the uses of
> edp_panel_vdd_off(intel_dp, true)
> vs. edp_panel_vdd_off_sync(intel_dp). In particular, why are there
> direct calls to the latter all over the place? Seems wrong.

edp_panel_vdd_off() should always be paired with a edp_panel_vdd_on().
If we were to call edp_panel_vdd_off() without the correct pairing we
would get a warning due to want_panel_vdd==false, whereas
edp_panel_vdd_off_sync() will now warn when want_panel_vdd==true.
The direct calls to edp_panel_vdd_off_sync() are in places where we
should not have want_panel_vdd==true (eg. system suspend) but we
just want to force vdd off even if the delayed off work has alrady
been scheduled.

> 
> BR,
> Jani.
> 
> 
> >
> > Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
> > ---
> >  drivers/gpu/drm/i915/intel_dp.c | 7 +++++--
> >  1 file changed, 5 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
> > index e6b4d4d..0fb510c 100644
> > --- a/drivers/gpu/drm/i915/intel_dp.c
> > +++ b/drivers/gpu/drm/i915/intel_dp.c
> > @@ -1241,7 +1241,9 @@ static void edp_panel_vdd_off_sync(struct intel_dp *intel_dp)
> >  
> >  	WARN_ON(!drm_modeset_is_locked(&dev->mode_config.connection_mutex));
> >  
> > -	if (intel_dp->want_panel_vdd || !edp_have_panel_vdd(intel_dp))
> > +	WARN_ON(intel_dp->want_panel_vdd);
> > +
> > +	if (!edp_have_panel_vdd(intel_dp))
> >  		return;
> >  
> >  	DRM_DEBUG_KMS("Turning eDP VDD off\n");
> > @@ -1273,7 +1275,8 @@ static void edp_panel_vdd_work(struct work_struct *__work)
> >  	struct drm_device *dev = intel_dp_to_dev(intel_dp);
> >  
> >  	drm_modeset_lock(&dev->mode_config.connection_mutex, NULL);
> > -	edp_panel_vdd_off_sync(intel_dp);
> > +	if (!intel_dp->want_panel_vdd)
> > +		edp_panel_vdd_off_sync(intel_dp);
> >  	drm_modeset_unlock(&dev->mode_config.connection_mutex);
> >  }
> >  
> > -- 
> > 1.8.5.5
> >
> > _______________________________________________
> > Intel-gfx mailing list
> > Intel-gfx@lists.freedesktop.org
> > http://lists.freedesktop.org/mailman/listinfo/intel-gfx
> 
> -- 
> Jani Nikula, Intel Open Source Technology Center

-- 
Ville Syrjälä
Intel OTC