[Intel-gfx] [PATCH 1/3] drm/i915: Wait for pending flips in intel_pipe_set_base()

[Chris Wilson]

On Thu,  1 Nov 2012 20:06:00 +0200, ville.syrjala at linux.intel.com wrote:
> From: Ville Syrjälä <ville.syrjala at linux.intel.com>
> 
> intel_pipe_set_base() never actually waited for any pending page flips
> on the CRTC. It looks like it tried to, by calling intel_finish_fb() on
> the current front buffer. But the pending flips were actually tracked
> in the BO of the previous front buffer, so the call to intel_finish_fb()
> never did anything useful.
> 
> Now even the pending_flip counter is gone, so we should just
> use intel_crtc_wait_for_pending_flips(), but since we're already holding
> struct_mutex when we would call that function, we need another version
> of it, that itself doesn't lock struct_mutex.
> 
> Signed-off-by: Ville Syrjälä <ville.syrjala at linux.intel.com>
> ---
>  drivers/gpu/drm/i915/intel_display.c |   51 +++++++++++++++++++++------------
>  1 files changed, 32 insertions(+), 19 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
> index 1a38267..7bf4749 100644
> --- a/drivers/gpu/drm/i915/intel_display.c
> +++ b/drivers/gpu/drm/i915/intel_display.c
> @@ -2228,6 +2228,37 @@ static void intel_crtc_update_sarea_pos(struct drm_crtc *crtc, int x, int y)
>  	}
>  }
>  
> +static bool intel_crtc_has_pending_flip(struct drm_crtc *crtc)
> +{
> +	struct drm_device *dev = crtc->dev;
> +	struct drm_i915_private *dev_priv = dev->dev_private;
> +	unsigned long flags;
> +	bool pending;
> +
> +	if (atomic_read(&dev_priv->mm.wedged))
> +		return false;
> +
> +	spin_lock_irqsave(&dev->event_lock, flags);
> +	pending = to_intel_crtc(crtc)->unpin_work != NULL;
> +	spin_unlock_irqrestore(&dev->event_lock, flags);
> +
> +	return pending;
> +}
> +
> +static void intel_crtc_wait_for_pending_flips_locked(struct drm_crtc *crtc)
> +{

Can we rearrange this such that the waiting logic is inside _locked()
and then intel_crtc_wiat_for_pending_flips() becomes a wrapper that
acquires the struct_mutex and then calls _locked()? Just to keep the
code simpler at the expense of the pathological case.
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre