Re: [PATCH 4/5] drm/i915: PSR VLV: Add single frame update.

[Daniel Vetter <daniel@ffwll.ch>]

On Fri, Apr 10, 2015 at 11:15:10AM -0700, Rodrigo Vivi wrote:
> According to spec: "In PSR HW or SW mode, SW set this bit before writing
> registers for a flip. It will be self-clear when it gets to the PSR
> active state."
> 
> Some versions of spec mention that this is needed when in
> "Persistent mode" but define it as same as "SW mode". Since this
> fix the page flip case let's assume this is exactly what we need.
> 
> Cc: Dhinakaran Pandiyan <dhinakaran.pandiyan@intel.com>
> Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>

Merged up to this one to dinq, will wait with the final enable until the
bug Matthew reported is a bit clearer.
-Daniel

> ---
>  drivers/gpu/drm/i915/intel_drv.h         |  1 +
>  drivers/gpu/drm/i915/intel_frontbuffer.c |  2 ++
>  drivers/gpu/drm/i915/intel_psr.c         | 42 ++++++++++++++++++++++++++++++++
>  3 files changed, 45 insertions(+)
> 
> diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
> index 7a0aa24..9c5d1cd 100644
> --- a/drivers/gpu/drm/i915/intel_drv.h
> +++ b/drivers/gpu/drm/i915/intel_drv.h
> @@ -1220,6 +1220,7 @@ void intel_psr_invalidate(struct drm_device *dev,
>  void intel_psr_flush(struct drm_device *dev,
>  			 unsigned frontbuffer_bits);
>  void intel_psr_init(struct drm_device *dev);
> +void intel_psr_single_frame_update(struct drm_device *dev);
>  
>  /* intel_runtime_pm.c */
>  int intel_power_domains_init(struct drm_i915_private *);
> diff --git a/drivers/gpu/drm/i915/intel_frontbuffer.c b/drivers/gpu/drm/i915/intel_frontbuffer.c
> index a20cffb..57095f5 100644
> --- a/drivers/gpu/drm/i915/intel_frontbuffer.c
> +++ b/drivers/gpu/drm/i915/intel_frontbuffer.c
> @@ -243,6 +243,8 @@ void intel_frontbuffer_flip_prepare(struct drm_device *dev,
>  	/* Remove stale busy bits due to the old buffer. */
>  	dev_priv->fb_tracking.busy_bits &= ~frontbuffer_bits;
>  	mutex_unlock(&dev_priv->fb_tracking.lock);
> +
> +	intel_psr_single_frame_update(dev);
>  }
>  
>  /**
> diff --git a/drivers/gpu/drm/i915/intel_psr.c b/drivers/gpu/drm/i915/intel_psr.c
> index 5cd374b..5ee0fa5 100644
> --- a/drivers/gpu/drm/i915/intel_psr.c
> +++ b/drivers/gpu/drm/i915/intel_psr.c
> @@ -594,6 +594,48 @@ static void intel_psr_exit(struct drm_device *dev)
>  }
>  
>  /**
> + * intel_psr_single_frame_update - Single Frame Update
> + * @dev: DRM device
> + *
> + * Some platforms support a single frame update feature that is used to
> + * send and update only one frame on Remote Frame Buffer.
> + * So far it is only implemented for Valleyview and Cherryview because
> + * hardware requires this to be done before a page flip.
> + */
> +void intel_psr_single_frame_update(struct drm_device *dev)
> +{
> +	struct drm_i915_private *dev_priv = dev->dev_private;
> +	struct drm_crtc *crtc;
> +	enum pipe pipe;
> +	u32 val;
> +
> +	/*
> +	 * Single frame update is already supported on BDW+ but it requires
> +	 * many W/A and it isn't really needed.
> +	 */
> +	if (!IS_VALLEYVIEW(dev))
> +		return;
> +
> +	mutex_lock(&dev_priv->psr.lock);
> +	if (!dev_priv->psr.enabled) {
> +		mutex_unlock(&dev_priv->psr.lock);
> +		return;
> +	}
> +
> +	crtc = dp_to_dig_port(dev_priv->psr.enabled)->base.base.crtc;
> +	pipe = to_intel_crtc(crtc)->pipe;
> +	val = I915_READ(VLV_PSRCTL(pipe));
> +
> +	/*
> +	 * We need to set this bit before writing registers for a flip.
> +	 * This bit will be self-clear when it gets to the PSR active state.
> +	 */
> +	I915_WRITE(VLV_PSRCTL(pipe), val | VLV_EDP_PSR_SINGLE_FRAME_UPDATE);
> +
> +	mutex_unlock(&dev_priv->psr.lock);
> +}
> +
> +/**
>   * intel_psr_invalidate - Invalidade PSR
>   * @dev: DRM device
>   * @frontbuffer_bits: frontbuffer plane tracking bits
> -- 
> 2.1.0
> 
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-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch
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