Re: [PATCH] drm/i915: Restarting the Idleness DRRS in drrs_flush

[Daniel Vetter <daniel@ffwll.ch>]

On Mon, Jun 15, 2015 at 08:50:05PM +0530, Ramalingam C wrote:
> Corrected the documentation on the intel_edp_drrs_flush and
> intel_edp_drrs_invalidate.
> 
> And accordingly edp_drrs_flush function is modified to restart the idleness
> detection after upclocking.
> 
> Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>

Thanks for testing and updating the comments. I've added a note to the
commit that the kerneldoc is from you and applied the patch.
-Daniel

> ---
>  drivers/gpu/drm/i915/intel_dp.c |   30 ++++++++++++++++++++----------
>  1 file changed, 20 insertions(+), 10 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
> index fb3d7f1..d5d5980 100644
> --- a/drivers/gpu/drm/i915/intel_dp.c
> +++ b/drivers/gpu/drm/i915/intel_dp.c
> @@ -5455,13 +5455,12 @@ unlock:
>  }
>  
>  /**
> - * intel_edp_drrs_invalidate - Invalidate DRRS
> + * intel_edp_drrs_invalidate - Disable Idleness DRRS
>   * @dev: DRM device
>   * @frontbuffer_bits: frontbuffer plane tracking bits
>   *
> - * When there is a disturbance on screen (due to cursor movement/time
> - * update etc), DRRS needs to be invalidated, i.e. need to switch to
> - * high RR.
> + * This function gets called everytime rendering on the given planes start.
> + * Hence DRRS needs to be Upclocked, i.e. (LOW_RR -> HIGH_RR).
>   *
>   * Dirty frontbuffers relevant to DRRS are tracked in busy_frontbuffer_bits.
>   */
> @@ -5486,6 +5485,7 @@ void intel_edp_drrs_invalidate(struct drm_device *dev,
>  	crtc = dp_to_dig_port(dev_priv->drrs.dp)->base.base.crtc;
>  	pipe = to_intel_crtc(crtc)->pipe;
>  
> +	/* invalidate means busy screen hence upclock */
>  	if (dev_priv->drrs.refresh_rate_type == DRRS_LOW_RR) {
>  		intel_dp_set_drrs_state(dev_priv->dev,
>  				dev_priv->drrs.dp->attached_connector->panel.
> @@ -5499,13 +5499,14 @@ void intel_edp_drrs_invalidate(struct drm_device *dev,
>  }
>  
>  /**
> - * intel_edp_drrs_flush - Flush DRRS
> + * intel_edp_drrs_flush - Restart Idleness DRRS
>   * @dev: DRM device
>   * @frontbuffer_bits: frontbuffer plane tracking bits
>   *
> - * When there is no movement on screen, DRRS work can be scheduled.
> - * This DRRS work is responsible for setting relevant registers after a
> - * timeout of 1 second.
> + * This function gets called every time rendering on the given planes has
> + * completed or flip on a crtc is completed. So DRRS should be upclocked
> + * (LOW_RR -> HIGH_RR). And also Idleness detection should be started again,
> + * if no other planes are dirty.
>   *
>   * Dirty frontbuffers relevant to DRRS are tracked in busy_frontbuffer_bits.
>   */
> @@ -5531,8 +5532,17 @@ void intel_edp_drrs_flush(struct drm_device *dev,
>  	pipe = to_intel_crtc(crtc)->pipe;
>  	dev_priv->drrs.busy_frontbuffer_bits &= ~frontbuffer_bits;
>  
> -	if (dev_priv->drrs.refresh_rate_type != DRRS_LOW_RR &&
> -			!dev_priv->drrs.busy_frontbuffer_bits)
> +	/* flush means busy screen hence upclock */
> +	if (dev_priv->drrs.refresh_rate_type == DRRS_LOW_RR)
> +		intel_dp_set_drrs_state(dev_priv->dev,
> +				dev_priv->drrs.dp->attached_connector->panel.
> +				fixed_mode->vrefresh);
> +
> +	/*
> +	 * flush also means no more activity hence schedule downclock, if all
> +	 * other fbs are quiescent too
> +	 */
> +	if (!dev_priv->drrs.busy_frontbuffer_bits)
>  		schedule_delayed_work(&dev_priv->drrs.work,
>  				msecs_to_jiffies(1000));
>  	mutex_unlock(&dev_priv->drrs.mutex);
> -- 
> 1.7.9.5
> 

-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch
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