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

[Dhinakaran Pandiyan]

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?



> +		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)