[Intel-gfx] [PATCH 02/17] drm/i915: Warn if stealing power sequencer from an active eDP port

[Ville Syrjälä]

On Tue, Oct 28, 2014 at 09:10:13AM +0100, Daniel Vetter wrote:
> On Thu, Oct 16, 2014 at 09:27:28PM +0300, ville.syrjala at linux.intel.com wrote:
> > From: Ville Syrjälä <ville.syrjala at linux.intel.com>
> > 
> > eDP ports need the power seqeuncer whenever the port is active. Warn if
> > we accidentally steal the power sequener from an active eDP port. This
> > should not happen unless there's a bug somewhere else, but it's best to
> > scream loudly if it happens to help with debugging.
> > 
> > Signed-off-by: Ville Syrjälä <ville.syrjala at linux.intel.com>
> > ---
> >  drivers/gpu/drm/i915/intel_dp.c | 4 ++++
> >  1 file changed, 4 insertions(+)
> > 
> > diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
> > index de919e9..7ac5c47 100644
> > --- a/drivers/gpu/drm/i915/intel_dp.c
> > +++ b/drivers/gpu/drm/i915/intel_dp.c
> > @@ -2606,6 +2606,10 @@ static void vlv_steal_power_sequencer(struct drm_device *dev,
> >  		DRM_DEBUG_KMS("stealing pipe %c power sequencer from port %c\n",
> >  			      pipe_name(pipe), port_name(port));
> >  
> > +		WARN(encoder->connectors_active,
> 
> This only checks for the pipe actually running, i.e. dpms on. But I guess
> we actually want to check for logically enabled (i.e. no matter the dpms
> state) to make sure we can always transition from dpms off to on again.
> That should check for encoder->base.crtc instead.

We can allow stealing the power sequencer whenever the port is not
running. When the port gets re-enabled the power seqeuencer gets
stolen back.

> 
> I'll punt on this patch until this is clarified.
> -Daniel
> 
> > +		     "stealing pipe %c power sequencer from active eDP port %c\n",
> > +		     pipe_name(pipe), port_name(port));
> > +
> >  		/* make sure vdd is off before we steal it */
> >  		edp_panel_vdd_off_sync(intel_dp);
> >  
> > -- 
> > 2.0.4
> > 
> > _______________________________________________
> > Intel-gfx mailing list
> > Intel-gfx at lists.freedesktop.org
> > http://lists.freedesktop.org/mailman/listinfo/intel-gfx
> 
> -- 
> Daniel Vetter
> Software Engineer, Intel Corporation
> +41 (0) 79 365 57 48 - http://blog.ffwll.ch

-- 
Ville Syrjälä
Intel OTC