Re: [PATCH 1/2] drm/i915/fbc: intel_fbc.crtc and intel_fbc.enabled are synonymous

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

On Fri, Oct 27, 2017 at 08:42:39PM +0100, Chris Wilson wrote:
> Slightly reduce the chance for confusion by only having one variable
> instead of two to tell us when intel_fbc is enabled on a crtc.
> 
> Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
> Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
> Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
> ---
>  drivers/gpu/drm/i915/i915_drv.h  |  1 -
>  drivers/gpu/drm/i915/intel_fbc.c | 33 +++++++++++++--------------------
>  2 files changed, 13 insertions(+), 21 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
> index 61c155cbf9d7..c0f8a13ec957 100644
> --- a/drivers/gpu/drm/i915/i915_drv.h
> +++ b/drivers/gpu/drm/i915/i915_drv.h
> @@ -1083,7 +1083,6 @@ struct intel_fbc {
>  
>  	bool false_color;
>  
> -	bool enabled;
>  	bool active;
>  
>  	bool underrun_detected;
> diff --git a/drivers/gpu/drm/i915/intel_fbc.c b/drivers/gpu/drm/i915/intel_fbc.c
> index 1a0f5e0c8d10..f4c3a3b9a8e6 100644
> --- a/drivers/gpu/drm/i915/intel_fbc.c
> +++ b/drivers/gpu/drm/i915/intel_fbc.c
> @@ -472,7 +472,7 @@ static void intel_fbc_schedule_activation(struct intel_crtc *crtc)
>  	struct intel_fbc_work *work = &fbc->work;
>  
>  	WARN_ON(!mutex_is_locked(&fbc->lock));
> -	if (WARN_ON(!fbc->enabled))
> +	if (WARN_ON(fbc->crtc != crtc))
>  		return;

I was a bit worried that this might trip needlessly, but looks like
__intel_fbc_post_update() should keep that from happening.

>  
>  	if (drm_crtc_vblank_get(&crtc->base)) {
> @@ -927,7 +927,7 @@ void intel_fbc_pre_update(struct intel_crtc *crtc,
>  		goto deactivate;
>  	}
>  
> -	if (!fbc->enabled || fbc->crtc != crtc)
> +	if (fbc->crtc != crtc)
>  		goto unlock;
>  
>  	intel_fbc_update_state_cache(crtc, crtc_state, plane_state);
> @@ -946,7 +946,7 @@ static void __intel_fbc_post_update(struct intel_crtc *crtc)
>  
>  	WARN_ON(!mutex_is_locked(&fbc->lock));
>  
> -	if (!fbc->enabled || fbc->crtc != crtc)
> +	if (fbc->crtc != crtc)
>  		return;
>  
>  	if (!intel_fbc_can_activate(crtc)) {
> @@ -986,7 +986,7 @@ void intel_fbc_post_update(struct intel_crtc *crtc)
>  
>  static unsigned int intel_fbc_get_frontbuffer_bit(struct intel_fbc *fbc)
>  {
> -	if (fbc->enabled)
> +	if (fbc->crtc)
>  		return to_intel_plane(fbc->crtc->base.primary)->frontbuffer_bit;
>  	else
>  		return fbc->possible_framebuffer_bits;
> @@ -1008,7 +1008,7 @@ void intel_fbc_invalidate(struct drm_i915_private *dev_priv,
>  
>  	fbc->busy_bits |= intel_fbc_get_frontbuffer_bit(fbc) & frontbuffer_bits;
>  
> -	if (fbc->enabled && fbc->busy_bits)
> +	if (fbc->crtc && fbc->busy_bits)
>  		intel_fbc_deactivate(dev_priv);
>  
>  	mutex_unlock(&fbc->lock);
> @@ -1029,7 +1029,7 @@ void intel_fbc_flush(struct drm_i915_private *dev_priv,
>  	if (origin == ORIGIN_GTT || origin == ORIGIN_FLIP)
>  		goto out;
>  
> -	if (!fbc->busy_bits && fbc->enabled &&
> +	if (!fbc->busy_bits && fbc->crtc &&
>  	    (frontbuffer_bits & intel_fbc_get_frontbuffer_bit(fbc))) {
>  		if (fbc->active)
>  			intel_fbc_recompress(dev_priv);
> @@ -1129,20 +1129,17 @@ void intel_fbc_enable(struct intel_crtc *crtc,
>  
>  	mutex_lock(&fbc->lock);
>  
> -	if (fbc->enabled) {
> -		WARN_ON(fbc->crtc == NULL);
> -		if (fbc->crtc == crtc) {
> -			WARN_ON(!crtc_state->enable_fbc);
> -			WARN_ON(fbc->active);
> -		}
> -		goto out;
> +	if (fbc->crtc == crtc) {
> +		WARN_ON(!crtc_state->enable_fbc);
> +		WARN_ON(fbc->active);
>  	}
> +	if (fbc->crtc)
> +		goto out;
>  
>  	if (!crtc_state->enable_fbc)
>  		goto out;
>  
>  	WARN_ON(fbc->active);
> -	WARN_ON(fbc->crtc != NULL);
>  
>  	intel_fbc_update_state_cache(crtc, crtc_state, plane_state);
>  	if (intel_fbc_alloc_cfb(crtc)) {
> @@ -1153,7 +1150,6 @@ void intel_fbc_enable(struct intel_crtc *crtc,
>  	DRM_DEBUG_KMS("Enabling FBC on pipe %c\n", pipe_name(crtc->pipe));
>  	fbc->no_fbc_reason = "FBC enabled but not active yet\n";
>  
> -	fbc->enabled = true;
>  	fbc->crtc = crtc;
>  out:
>  	mutex_unlock(&fbc->lock);
> @@ -1172,7 +1168,6 @@ static void __intel_fbc_disable(struct drm_i915_private *dev_priv)
>  	struct intel_crtc *crtc = fbc->crtc;
>  
>  	WARN_ON(!mutex_is_locked(&fbc->lock));
> -	WARN_ON(!fbc->enabled);

WARN(!crtc) maybe? Though the callers are pretty clear, so not sure it's
even worth it.

Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>

>  	WARN_ON(fbc->active);
>  	WARN_ON(crtc->active);
>  
> @@ -1180,7 +1175,6 @@ static void __intel_fbc_disable(struct drm_i915_private *dev_priv)
>  
>  	__intel_fbc_cleanup_cfb(dev_priv);
>  
> -	fbc->enabled = false;
>  	fbc->crtc = NULL;
>  }
>  
> @@ -1220,7 +1214,7 @@ void intel_fbc_global_disable(struct drm_i915_private *dev_priv)
>  		return;
>  
>  	mutex_lock(&fbc->lock);
> -	if (fbc->enabled)
> +	if (fbc->crtc)
>  		__intel_fbc_disable(dev_priv);
>  	mutex_unlock(&fbc->lock);
>  
> @@ -1236,7 +1230,7 @@ static void intel_fbc_underrun_work_fn(struct work_struct *work)
>  	mutex_lock(&fbc->lock);
>  
>  	/* Maybe we were scheduled twice. */
> -	if (fbc->underrun_detected || !fbc->enabled)
> +	if (fbc->underrun_detected || !fbc->crtc)
>  		goto out;
>  
>  	DRM_DEBUG_KMS("Disabling FBC due to FIFO underrun.\n");
> @@ -1351,7 +1345,6 @@ void intel_fbc_init(struct drm_i915_private *dev_priv)
>  	INIT_WORK(&fbc->work.work, intel_fbc_work_fn);
>  	INIT_WORK(&fbc->underrun_work, intel_fbc_underrun_work_fn);
>  	mutex_init(&fbc->lock);
> -	fbc->enabled = false;
>  	fbc->active = false;
>  	fbc->work.scheduled = false;
>  
> -- 
> 2.15.0.rc2
> 
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-- 
Ville Syrjälä
Intel OTC
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