Re: [PATCH 2/6] drm/i915: Remove intel_prepare_page_flip.

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

On Wed, Mar 23, 2016 at 02:24:28PM +0100, Maarten Lankhorst wrote:
> Do it in 1 step instead, use atomic_read since INTEL_FLIP_COMPLETE
> is no longer useful.
> 
> Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
> ---
>  drivers/gpu/drm/i915/i915_debugfs.c  |  3 --
>  drivers/gpu/drm/i915/i915_irq.c      | 18 ++-----
>  drivers/gpu/drm/i915/intel_display.c | 96 ++++++++++++++----------------------
>  drivers/gpu/drm/i915/intel_drv.h     |  2 -
>  4 files changed, 40 insertions(+), 79 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/i915_debugfs.c b/drivers/gpu/drm/i915/i915_debugfs.c
> index 310043d73bf7..4a0078c17cd1 100644
> --- a/drivers/gpu/drm/i915/i915_debugfs.c
> +++ b/drivers/gpu/drm/i915/i915_debugfs.c
> @@ -588,9 +588,6 @@ static int i915_gem_pageflip_info(struct seq_file *m, void *data)
>  			if (pending == INTEL_FLIP_INACTIVE) {
>  				seq_printf(m, "Flip ioctl preparing on pipe %c (plane %c)\n",
>  					   pipe, plane);
> -			} else if (pending >= INTEL_FLIP_COMPLETE) {
> -				seq_printf(m, "Flip queued on pipe %c (plane %c)\n",
> -					   pipe, plane);
>  			} else {
>  				seq_printf(m, "Flip pending (waiting for vsync) on pipe %c (plane %c)\n",
>  					   pipe, plane);
> diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c
> index a55a7cc317f8..9d4089f6c91b 100644
> --- a/drivers/gpu/drm/i915/i915_irq.c
> +++ b/drivers/gpu/drm/i915/i915_irq.c
> @@ -1707,10 +1707,8 @@ static void valleyview_pipestat_irq_handler(struct drm_device *dev, u32 iir)
>  		    intel_pipe_handle_vblank(dev, pipe))
>  			intel_check_page_flip(dev, pipe);
>  
> -		if (pipe_stats[pipe] & PLANE_FLIP_DONE_INT_STATUS_VLV) {
> -			intel_prepare_page_flip(dev, pipe);
> +		if (pipe_stats[pipe] & PLANE_FLIP_DONE_INT_STATUS_VLV)
>  			intel_finish_page_flip(dev, pipe);
> -		}
>  
>  		if (pipe_stats[pipe] & PIPE_CRC_DONE_INTERRUPT_STATUS)
>  			i9xx_pipe_crc_irq_handler(dev, pipe);
> @@ -2109,10 +2107,8 @@ static void ilk_display_irq_handler(struct drm_device *dev, u32 de_iir)
>  			i9xx_pipe_crc_irq_handler(dev, pipe);
>  
>  		/* plane/pipes map 1:1 on ilk+ */
> -		if (de_iir & DE_PLANE_FLIP_DONE(pipe)) {
> -			intel_prepare_page_flip(dev, pipe);
> +		if (de_iir & DE_PLANE_FLIP_DONE(pipe))
>  			intel_finish_page_flip_plane(dev, pipe);
> -		}
>  	}
>  
>  	/* check event from PCH */
> @@ -2156,10 +2152,8 @@ static void ivb_display_irq_handler(struct drm_device *dev, u32 de_iir)
>  			intel_check_page_flip(dev, pipe);
>  
>  		/* plane/pipes map 1:1 on ilk+ */
> -		if (de_iir & DE_PLANE_FLIP_DONE_IVB(pipe)) {
> -			intel_prepare_page_flip(dev, pipe);
> +		if (de_iir & DE_PLANE_FLIP_DONE_IVB(pipe))
>  			intel_finish_page_flip_plane(dev, pipe);
> -		}
>  	}
>  
>  	/* check event from PCH */
> @@ -2363,10 +2357,8 @@ gen8_de_irq_handler(struct drm_i915_private *dev_priv, u32 master_ctl)
>  		else
>  			flip_done &= GEN8_PIPE_PRIMARY_FLIP_DONE;
>  
> -		if (flip_done) {
> -			intel_prepare_page_flip(dev, pipe);
> +		if (flip_done)
>  			intel_finish_page_flip_plane(dev, pipe);
> -		}
>  
>  		if (iir & GEN8_PIPE_CDCLK_CRC_DONE)
>  			hsw_pipe_crc_irq_handler(dev, pipe);
> @@ -3984,7 +3976,6 @@ static bool i8xx_handle_vblank(struct drm_device *dev,
>  	if (I915_READ16(ISR) & flip_pending)
>  		goto check_page_flip;
>  
> -	intel_prepare_page_flip(dev, plane);
>  	intel_finish_page_flip(dev, pipe);
>  	return true;
>  
> @@ -4175,7 +4166,6 @@ static bool i915_handle_vblank(struct drm_device *dev,
>  	if (I915_READ(ISR) & flip_pending)
>  		goto check_page_flip;
>  
> -	intel_prepare_page_flip(dev, plane);
>  	intel_finish_page_flip(dev, pipe);
>  	return true;
>  
> diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
> index 6303438df9f2..c15c08dc251c 100644
> --- a/drivers/gpu/drm/i915/intel_display.c
> +++ b/drivers/gpu/drm/i915/intel_display.c
> @@ -3138,7 +3138,6 @@ static void intel_complete_page_flips(struct drm_device *dev)
>  		struct intel_crtc *intel_crtc = to_intel_crtc(crtc);
>  		enum plane plane = intel_crtc->plane;
>  
> -		intel_prepare_page_flip(dev, plane);
>  		intel_finish_page_flip_plane(dev, plane);
>  	}
>  }
> @@ -10825,53 +10824,6 @@ static void intel_unpin_work_fn(struct work_struct *__work)
>  	kfree(work);
>  }
>  
> -static void do_intel_finish_page_flip(struct drm_device *dev,
> -				      struct drm_crtc *crtc)
> -{
> -	struct intel_crtc *intel_crtc = to_intel_crtc(crtc);
> -	struct intel_unpin_work *work;
> -	unsigned long flags;
> -
> -	/* Ignore early vblank irqs */
> -	if (intel_crtc == NULL)
> -		return;
> -
> -	/*
> -	 * This is called both by irq handlers and the reset code (to complete
> -	 * lost pageflips) so needs the full irqsave spinlocks.
> -	 */
> -	spin_lock_irqsave(&dev->event_lock, flags);
> -	work = intel_crtc->unpin_work;
> -
> -	/* Ensure we don't miss a work->pending update ... */
> -	smp_rmb();
> -
> -	if (work == NULL || atomic_read(&work->pending) < INTEL_FLIP_COMPLETE) {
> -		spin_unlock_irqrestore(&dev->event_lock, flags);
> -		return;
> -	}
> -
> -	page_flip_completed(intel_crtc);
> -
> -	spin_unlock_irqrestore(&dev->event_lock, flags);
> -}
> -
> -void intel_finish_page_flip(struct drm_device *dev, int pipe)
> -{
> -	struct drm_i915_private *dev_priv = dev->dev_private;
> -	struct drm_crtc *crtc = dev_priv->pipe_to_crtc_mapping[pipe];
> -
> -	do_intel_finish_page_flip(dev, crtc);
> -}
> -
> -void intel_finish_page_flip_plane(struct drm_device *dev, int plane)
> -{
> -	struct drm_i915_private *dev_priv = dev->dev_private;
> -	struct drm_crtc *crtc = dev_priv->plane_to_crtc_mapping[plane];
> -
> -	do_intel_finish_page_flip(dev, crtc);
> -}
> -
>  /* Is 'a' after or equal to 'b'? */
>  static bool g4x_flip_count_after_eq(u32 a, u32 b)
>  {
> @@ -10924,28 +10876,52 @@ static bool page_flip_finished(struct intel_crtc *crtc)
>  				    crtc->unpin_work->flip_count);
>  }
>  
> -void intel_prepare_page_flip(struct drm_device *dev, int plane)
> +static void do_intel_finish_page_flip(struct drm_device *dev,
> +				      struct drm_crtc *crtc)
>  {
> -	struct drm_i915_private *dev_priv = dev->dev_private;
> -	struct intel_crtc *intel_crtc =
> -		to_intel_crtc(dev_priv->plane_to_crtc_mapping[plane]);
> +	struct intel_crtc *intel_crtc = to_intel_crtc(crtc);
> +	struct intel_unpin_work *work;
>  	unsigned long flags;
>  
> +	/* Ignore early vblank irqs */
> +	if (intel_crtc == NULL)
> +		return;
>  
>  	/*
>  	 * This is called both by irq handlers and the reset code (to complete
>  	 * lost pageflips) so needs the full irqsave spinlocks.
> -	 *
> -	 * NB: An MMIO update of the plane base pointer will also
> -	 * generate a page-flip completion irq, i.e. every modeset
> -	 * is also accompanied by a spurious intel_prepare_page_flip().
>  	 */
>  	spin_lock_irqsave(&dev->event_lock, flags);
> -	if (intel_crtc->unpin_work && page_flip_finished(intel_crtc))
> -		atomic_inc_not_zero(&intel_crtc->unpin_work->pending);
> +	work = intel_crtc->unpin_work;
> +
> +	if (work == NULL ||
> +	    atomic_read(&work->pending) == INTEL_FLIP_INACTIVE ||
> +	   !page_flip_finished(intel_crtc)) {
> +		spin_unlock_irqrestore(&dev->event_lock, flags);
> +		return;
> +	}
> +
> +	page_flip_completed(intel_crtc);
> +
>  	spin_unlock_irqrestore(&dev->event_lock, flags);
>  }
>  
> +void intel_finish_page_flip(struct drm_device *dev, int pipe)
> +{
> +	struct drm_i915_private *dev_priv = dev->dev_private;
> +	struct drm_crtc *crtc = dev_priv->pipe_to_crtc_mapping[pipe];
> +
> +	do_intel_finish_page_flip(dev, crtc);
> +}
> +
> +void intel_finish_page_flip_plane(struct drm_device *dev, int plane)
> +{
> +	struct drm_i915_private *dev_priv = dev->dev_private;
> +	struct drm_crtc *crtc = dev_priv->plane_to_crtc_mapping[plane];
> +
> +	do_intel_finish_page_flip(dev, crtc);
> +}

I don't think you need the _plane() variant anywhere actually, so might
as well kill it.

And since this patch is non-controversial I'd move it to the head of the
series.

> +
>  static inline void intel_mark_page_flip_active(struct intel_unpin_work *work)
>  {
>  	/* Ensure that the work item is consistent when activating it ... */
> @@ -11395,8 +11371,8 @@ static bool __intel_pageflip_stall_check(struct drm_device *dev,
>  	u32 pending;
>  
>  	pending = atomic_read(&work->pending);
> -	if (pending != INTEL_FLIP_PENDING)
> -		return pending == INTEL_FLIP_COMPLETE;
> +	if (pending == INTEL_FLIP_INACTIVE)
> +		return false;
>  
>  	if (work->flip_ready_vblank == 0) {
>  		if (work->flip_queued_req &&
> diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
> index 7f0779783851..e26293ead94f 100644
> --- a/drivers/gpu/drm/i915/intel_drv.h
> +++ b/drivers/gpu/drm/i915/intel_drv.h
> @@ -944,7 +944,6 @@ struct intel_unpin_work {
>  	atomic_t pending;
>  #define INTEL_FLIP_INACTIVE	0
>  #define INTEL_FLIP_PENDING	1
> -#define INTEL_FLIP_COMPLETE	2
>  	u32 flip_count;
>  	u32 gtt_offset;
>  	struct drm_i915_gem_request *flip_queued_req;
> @@ -1155,7 +1154,6 @@ struct drm_framebuffer *
>  __intel_framebuffer_create(struct drm_device *dev,
>  			   struct drm_mode_fb_cmd2 *mode_cmd,
>  			   struct drm_i915_gem_object *obj);
> -void intel_prepare_page_flip(struct drm_device *dev, int plane);
>  void intel_finish_page_flip(struct drm_device *dev, int pipe);
>  void intel_finish_page_flip_plane(struct drm_device *dev, int plane);
>  void intel_check_page_flip(struct drm_device *dev, int pipe);
> -- 
> 2.1.0
> 
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-- 
Ville Syrjälä
Intel OTC
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