[Intel-gfx] [PATCH] drm/i915: Handle changing enable_psr parameter at runtime better

[Pandiyan, Dhinakaran]

On Wed, 2018-03-07 at 17:39 +0100, Maarten Lankhorst wrote:
> Similar to enable_fbc, enable_psr was ignored at runtime if it was
> changed. The easiest fix is to pretend enable_psr is ignored at
> configure time, and never activate it for !enable_psr, so both cases
> are handled without modesets.

What about cases where psr_flush() is not called and consequently the
module parameter is not checked? With HW tracking, PSR is
enabled/disabled during modeset and the hardware is expected to exit and
activate PSR without driver intervention.


> Signed-off-by: Maarten Lankhorst <maarten.lankhorst at linux.intel.com>
> Tested-by: Benjamin Berg <bberg at redhat.com>
> Cc: Benjamin Berg <bberg at redhat.com>
> ---
>  drivers/gpu/drm/i915/intel_psr.c | 19 ++++++++++---------
>  1 file changed, 10 insertions(+), 9 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/intel_psr.c b/drivers/gpu/drm/i915/intel_psr.c
> index 23175c5c4a50..ac3ce7a1c2a7 100644
> --- a/drivers/gpu/drm/i915/intel_psr.c
> +++ b/drivers/gpu/drm/i915/intel_psr.c
> @@ -502,11 +502,6 @@ void intel_psr_compute_config(struct intel_dp *intel_dp,
>  	if (!CAN_PSR(dev_priv))
>  		return;
>  
> -	if (!i915_modparams.enable_psr) {
> -		DRM_DEBUG_KMS("PSR disable by flag\n");
> -		return;
> -	}
> -
>  	/*
>  	 * HSW spec explicitly says PSR is tied to port A.
>  	 * BDW+ platforms with DDI implementation of PSR have different
> @@ -559,7 +554,10 @@ void intel_psr_compute_config(struct intel_dp *intel_dp,
>  
>  	crtc_state->has_psr = true;
>  	crtc_state->has_psr2 = intel_psr2_config_valid(intel_dp, crtc_state);
> -	DRM_DEBUG_KMS("Enabling PSR%s\n", crtc_state->has_psr2 ? "2" : "");
> +	if (i915_modparams.enable_psr)
> +		DRM_DEBUG_KMS("Enabling PSR%s\n", crtc_state->has_psr2 ? "2" : "");
> +	else
> +		DRM_DEBUG_KMS("PSR disable by flag\n");
>  }
>  
>  static void intel_psr_activate(struct intel_dp *intel_dp)
> @@ -652,7 +650,9 @@ void intel_psr_enable(struct intel_dp *intel_dp,
>  	dev_priv->psr.enable_source(intel_dp, crtc_state);
>  	dev_priv->psr.enabled = intel_dp;
>  
> -	if (INTEL_GEN(dev_priv) >= 9) {
> +	if (!i915_modparams.enable_psr) {
> +		DRM_DEBUG_KMS("PSR disable by flag\n");
> +	} else if (INTEL_GEN(dev_priv) >= 9) {
>  		intel_psr_activate(intel_dp);
>  	} else {
>  		/*
> @@ -843,7 +843,7 @@ static void intel_psr_work(struct work_struct *work)
>  	 * recheck. Since psr_flush first clears this and then reschedules we
>  	 * won't ever miss a flush when bailing out here.
>  	 */
> -	if (dev_priv->psr.busy_frontbuffer_bits)
> +	if (dev_priv->psr.busy_frontbuffer_bits || !i915_modparams.enable_psr)
>  		goto unlock;
>  
>  	intel_psr_activate(intel_dp);
> @@ -1015,7 +1015,8 @@ void intel_psr_flush(struct drm_i915_private *dev_priv,
>  		return;
>  
>  	mutex_lock(&dev_priv->psr.lock);
> -	if (!dev_priv->psr.enabled) {
> +	if (!dev_priv->psr.enabled || !i915_modparams.enable_psr) {
> +		intel_psr_exit(dev_priv);
>  		mutex_unlock(&dev_priv->psr.lock);
>  		return;
>  	}