Re: [PATCH 1/9] drm/i915: Clear fb_tracking.busy_bits also for synchronous flips

["Ville Syrjälä" <ville.syrjala@linux.intel.com>]

On Thu, Jun 18, 2015 at 10:30:20AM +0200, Daniel Vetter wrote:
> The current/old frontbuffer might still have gpu frontbuffer rendering
> pending. But once flipped it won't have the corresponding frontbuffer
> bits any more and hence the request retire function won't ever clear
> the corresponding busy bits. The async flip tracking (with the
> flip_prepare and flip_complete functions) already does this, but
> somehow I've forgotten to do this for synchronous flips.
> 
> Note that we don't track outstanding rendering of the new framebuffer
> with busy_bits since all our plane update code waits for previous
> rendering to complete before displaying a new buffer. Hence a new
> buffer will never be busy.
> 
> Reported-by: Paulo Zanoni <przanoni@gmail.com>
> Cc: Paulo Zanoni <przanoni@gmail.com>
> Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
> ---
> Paulo promised to also extend kms_frontbuffer_tracking with flip vs.
> busy buffer tests.
> ---
>  drivers/gpu/drm/i915/intel_drv.h         | 18 ++----------------
>  drivers/gpu/drm/i915/intel_frontbuffer.c | 26 ++++++++++++++++++++++++++
>  2 files changed, 28 insertions(+), 16 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
> index bcafefcf048b..b7c69460fb20 100644
> --- a/drivers/gpu/drm/i915/intel_drv.h
> +++ b/drivers/gpu/drm/i915/intel_drv.h
> @@ -963,23 +963,9 @@ void intel_frontbuffer_flip_complete(struct drm_device *dev,
>  				     unsigned frontbuffer_bits);
>  void intel_frontbuffer_flush(struct drm_device *dev,
>  			     unsigned frontbuffer_bits);
> -/**
> - * intel_frontbuffer_flip - synchronous frontbuffer flip
> - * @dev: DRM device
> - * @frontbuffer_bits: frontbuffer plane tracking bits
> - *
> - * This function gets called after scheduling a flip on @obj. This is for
> - * synchronous plane updates which will happen on the next vblank and which will
> - * not get delayed by pending gpu rendering.
> - *
> - * Can be called without any locks held.
> - */
> -static inline
> +inline

inline?

>  void intel_frontbuffer_flip(struct drm_device *dev,
> -			    unsigned frontbuffer_bits)
> -{
> -	intel_frontbuffer_flush(dev, frontbuffer_bits);
> -}
> +			    unsigned frontbuffer_bits);
>  
>  unsigned int intel_fb_align_height(struct drm_device *dev,
>  				   unsigned int height,
> diff --git a/drivers/gpu/drm/i915/intel_frontbuffer.c b/drivers/gpu/drm/i915/intel_frontbuffer.c
> index 57095f54c1f2..2a1611a7ce1d 100644
> --- a/drivers/gpu/drm/i915/intel_frontbuffer.c
> +++ b/drivers/gpu/drm/i915/intel_frontbuffer.c
> @@ -270,3 +270,29 @@ void intel_frontbuffer_flip_complete(struct drm_device *dev,
>  
>  	intel_frontbuffer_flush(dev, frontbuffer_bits);
>  }
> +
> +/**
> + * intel_frontbuffer_flip - synchronous frontbuffer flip
> + * @dev: DRM device
> + * @frontbuffer_bits: frontbuffer plane tracking bits
> + *
> + * This function gets called after scheduling a flip on @obj. This is for
> + * synchronous plane updates which will happen on the next vblank and which will
> + * not get delayed by pending gpu rendering.
> + *
> + * Can be called without any locks held.
> + */
> +inline
> +void intel_frontbuffer_flip(struct drm_device *dev,
> +			    unsigned frontbuffer_bits)
> +{
> +	struct drm_i915_private *dev_priv = dev->dev_private;
> +
> +	mutex_lock(&dev_priv->fb_tracking.lock);
> +	dev_priv->fb_tracking.flip_bits |= frontbuffer_bits;
> +	/* 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_frontbuffer_flush(dev, frontbuffer_bits);
> +}
> -- 
> 2.1.0
> 
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-- 
Ville Syrjälä
Intel OTC
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