[Intel-gfx] [PATCH 1/4] drm/i915/psr: Always wait for idle state when disabling PSR

[Souza, Jose]

On Mon, 2018-10-08 at 15:43 -0700, Dhinakaran Pandiyan wrote:
> On Fri, 2018-10-05 at 16:35 -0700, José Roberto de Souza wrote:
> > It should always wait for idle state when disabling PSR because PSR
> > could be inactive due a call to intel_psr_exit() and while PSR is
> > still being disabled asynchronously userspace could change the
> > modeset causing a call to psr_disable() that will not wait for PSR
> > idle and then PSR will be enabled again while PSR is still not
> > idle.
> Agreed.
> 
> > Cc: Rodrigo Vivi <rodrigo.vivi at intel.com>
> > Cc: Dhinakaran Pandiyan <dhinakaran.pandiyan at intel.com>
> > Signed-off-by: José Roberto de Souza <jose.souza at intel.com>
> > ---
> >  drivers/gpu/drm/i915/intel_psr.c | 43 +++++++++++++++-------------
> > --
> > --
> >  1 file changed, 20 insertions(+), 23 deletions(-)
> > 
> > diff --git a/drivers/gpu/drm/i915/intel_psr.c
> > b/drivers/gpu/drm/i915/intel_psr.c
> > index 423cdf84059c..cd9a60d1efa1 100644
> > --- a/drivers/gpu/drm/i915/intel_psr.c
> > +++ b/drivers/gpu/drm/i915/intel_psr.c
> > @@ -661,40 +661,37 @@ static void
> >  intel_psr_disable_source(struct intel_dp *intel_dp)
> >  {
> >  	struct drm_i915_private *dev_priv = dp_to_i915(intel_dp);
> > +	i915_reg_t psr_status;
> > +	u32 psr_status_mask;
> >  
> >  	if (dev_priv->psr.active) {
> > -		i915_reg_t psr_status;
> > -		u32 psr_status_mask;
> > -
> > -		if (dev_priv->psr.psr2_enabled) {
> > -			psr_status = EDP_PSR2_STATUS;
> > -			psr_status_mask = EDP_PSR2_STATUS_STATE_MASK;
> > -
> > +		if (dev_priv->psr.psr2_enabled)
> >  			I915_WRITE(EDP_PSR2_CTL,
> > -				   I915_READ(EDP_PSR2_CTL) &
> > -				   ~(EDP_PSR2_ENABLE |
> > EDP_SU_TRACK_ENABLE));
> > -
> > -		} else {
> > -			psr_status = EDP_PSR_STATUS;
> > -			psr_status_mask = EDP_PSR_STATUS_STATE_MASK;
> > -
> > +				   I915_READ(EDP_PSR2_CTL) &
> > ~EDP_PSR2_ENABLE);
> 
> Is there a way to reuse psr_exit() and move rest of the stuff to the
> caller? We won't not need disable_source() if that can be done?

We could move to the caller and reuse psr_exit(), I will do that in
another patch.

> 
> 
> 
> > +		else
> >  			I915_WRITE(EDP_PSR_CTL,
> >  				   I915_READ(EDP_PSR_CTL) &
> > ~EDP_PSR_ENABLE);
> > -		}
> > -
> > -		/* Wait till PSR is idle */
> > -		if (intel_wait_for_register(dev_priv,
> > -					    psr_status,
> > psr_status_mask, 0,
> > -					    2000))
> > -			DRM_ERROR("Timed out waiting for PSR Idle
> > State\n");
> > -
> > -		dev_priv->psr.active = false;
> >  	} else {
> >  		if (dev_priv->psr.psr2_enabled)
> >  			WARN_ON(I915_READ(EDP_PSR2_CTL) &
> > EDP_PSR2_ENABLE);
> >  		else
> >  			WARN_ON(I915_READ(EDP_PSR_CTL) &
> > EDP_PSR_ENABLE);
> >  	}
> > +
> > +	if (dev_priv->psr.psr2_enabled) {
> > +		psr_status = EDP_PSR2_STATUS;
> > +		psr_status_mask = EDP_PSR2_STATUS_STATE_MASK;
> > +	} else {
> > +		psr_status = EDP_PSR_STATUS;
> > +		psr_status_mask = EDP_PSR_STATUS_STATE_MASK;
> > +	}
> > +
> > +	/* Wait till PSR is idle */
> > +	if (intel_wait_for_register(dev_priv, psr_status,
> > psr_status_mask, 0,
> > +				    2000))
> > +		DRM_ERROR("Timed out waiting for PSR Idle State\n");
> > +
> > +	dev_priv->psr.active = false;
> >  }
> >  
> >  static void intel_psr_disable_locked(struct intel_dp *intel_dp)
> 
> 
>