Re: [PATCH 01/11] drm: add drm_send_vblank_event() helper (v3)

[Marcin Slusarz <marcin.slusarz@gmail.com>]

On Thu, Oct 11, 2012 at 07:29:15PM -0500, Rob Clark wrote:
> From: Rob Clark <rob@ti.com>
> 
> A helper that drivers can use to send vblank event after a pageflip.
> If the driver doesn't support proper vblank irq based time/seqn then
> just pass -1 for the pipe # to get do_gettimestamp() behavior (since
> there are a lot of drivers that don't use drm_vblank_count_and_time())
> 
> Also an internal send_vblank_event() helper for the various other code
> paths within drm_irq that also need to send vblank events.
> 
> v1: original
> v2: add back 'vblwait->reply.sequence = seq' which should not have
>     been deleted
> v3: add WARN_ON() in case lock is not held and comments
> 
> Signed-off-by: Rob Clark <rob@ti.com>
> ---
>  drivers/gpu/drm/drm_irq.c |   74 +++++++++++++++++++++++++++++++--------------
>  include/drm/drmP.h        |    2 ++
>  2 files changed, 54 insertions(+), 22 deletions(-)
> 
> diff --git a/drivers/gpu/drm/drm_irq.c b/drivers/gpu/drm/drm_irq.c
> index 076c4a8..d623a06 100644
> --- a/drivers/gpu/drm/drm_irq.c
> +++ b/drivers/gpu/drm/drm_irq.c
> @@ -802,6 +802,46 @@ u32 drm_vblank_count_and_time(struct drm_device *dev, int crtc,
>  }
>  EXPORT_SYMBOL(drm_vblank_count_and_time);
>  
> +static void send_vblank_event(struct drm_device *dev,
> +		struct drm_pending_vblank_event *e,
> +		unsigned long seq, struct timeval *now)
> +{
> +	WARN_ON(!spin_is_locked(&dev->event_lock));

This should be WARN_ON_SMP - on !SMP && !DEBUG_SPINLOCK spin_is_locked always returns 0.

> +	e->event.sequence = seq;
> +	e->event.tv_sec = now->tv_sec;
> +	e->event.tv_usec = now->tv_usec;
> +
> +	list_add_tail(&e->base.link,
> +		      &e->base.file_priv->event_list);
> +	wake_up_interruptible(&e->base.file_priv->event_wait);
> +	trace_drm_vblank_event_delivered(e->base.pid, e->pipe,
> +					 e->event.sequence);
> +}
> +
> +/**
> + * drm_send_vblank_event - helper to send vblank event after pageflip
> + * @dev: DRM device
> + * @crtc: CRTC in question
> + * @e: the event to send
> + *
> + * Updates sequence # and timestamp on event, and sends it to userspace.
> + * Caller must hold event lock.
> + */
> +void drm_send_vblank_event(struct drm_device *dev, int crtc,
> +		struct drm_pending_vblank_event *e)
> +{
> +	struct timeval now;
> +	unsigned int seq;
> +	if (crtc >= 0) {
> +		seq = drm_vblank_count_and_time(dev, crtc, &now);
> +	} else {
> +		seq = 0;
> +		do_gettimeofday(&now);
> +	}
> +	send_vblank_event(dev, e, seq, &now);
> +}
> +EXPORT_SYMBOL(drm_send_vblank_event);
> +
>  /**
>   * drm_update_vblank_count - update the master vblank counter
>   * @dev: DRM device
> @@ -936,6 +976,13 @@ void drm_vblank_put(struct drm_device *dev, int crtc)
>  }
>  EXPORT_SYMBOL(drm_vblank_put);
>  
> +/**
> + * drm_vblank_off - disable vblank events on a CRTC
> + * @dev: DRM device
> + * @crtc: CRTC in question
> + *
> + * Caller must hold event lock.
> + */
>  void drm_vblank_off(struct drm_device *dev, int crtc)
>  {
>  	struct drm_pending_vblank_event *e, *t;
> @@ -955,15 +1002,9 @@ void drm_vblank_off(struct drm_device *dev, int crtc)
>  		DRM_DEBUG("Sending premature vblank event on disable: \
>  			  wanted %d, current %d\n",
>  			  e->event.sequence, seq);
> -
> -		e->event.sequence = seq;
> -		e->event.tv_sec = now.tv_sec;
> -		e->event.tv_usec = now.tv_usec;
> +		list_del(&e->base.link);
>  		drm_vblank_put(dev, e->pipe);
> -		list_move_tail(&e->base.link, &e->base.file_priv->event_list);
> -		wake_up_interruptible(&e->base.file_priv->event_wait);
> -		trace_drm_vblank_event_delivered(e->base.pid, e->pipe,
> -						 e->event.sequence);
> +		send_vblank_event(dev, e, seq, &now);
>  	}
>  
>  	spin_unlock_irqrestore(&dev->vbl_lock, irqflags);
> @@ -1107,15 +1148,9 @@ static int drm_queue_vblank_event(struct drm_device *dev, int pipe,
>  
>  	e->event.sequence = vblwait->request.sequence;
>  	if ((seq - vblwait->request.sequence) <= (1 << 23)) {
> -		e->event.sequence = seq;
> -		e->event.tv_sec = now.tv_sec;
> -		e->event.tv_usec = now.tv_usec;
>  		drm_vblank_put(dev, pipe);
> -		list_add_tail(&e->base.link, &e->base.file_priv->event_list);
> -		wake_up_interruptible(&e->base.file_priv->event_wait);
> +		send_vblank_event(dev, e, seq, &now);
>  		vblwait->reply.sequence = seq;
> -		trace_drm_vblank_event_delivered(current->pid, pipe,
> -						 vblwait->request.sequence);
>  	} else {
>  		/* drm_handle_vblank_events will call drm_vblank_put */
>  		list_add_tail(&e->base.link, &dev->vblank_event_list);
> @@ -1256,14 +1291,9 @@ static void drm_handle_vblank_events(struct drm_device *dev, int crtc)
>  		DRM_DEBUG("vblank event on %d, current %d\n",
>  			  e->event.sequence, seq);
>  
> -		e->event.sequence = seq;
> -		e->event.tv_sec = now.tv_sec;
> -		e->event.tv_usec = now.tv_usec;
> +		list_del(&e->base.link);
>  		drm_vblank_put(dev, e->pipe);
> -		list_move_tail(&e->base.link, &e->base.file_priv->event_list);
> -		wake_up_interruptible(&e->base.file_priv->event_wait);
> -		trace_drm_vblank_event_delivered(e->base.pid, e->pipe,
> -						 e->event.sequence);
> +		send_vblank_event(dev, e, seq, &now);
>  	}
>  
>  	spin_unlock_irqrestore(&dev->event_lock, flags);
> diff --git a/include/drm/drmP.h b/include/drm/drmP.h
> index 05af0e7..ee8f927 100644
> --- a/include/drm/drmP.h
> +++ b/include/drm/drmP.h
> @@ -1437,6 +1437,8 @@ extern int drm_vblank_wait(struct drm_device *dev, unsigned int *vbl_seq);
>  extern u32 drm_vblank_count(struct drm_device *dev, int crtc);
>  extern u32 drm_vblank_count_and_time(struct drm_device *dev, int crtc,
>  				     struct timeval *vblanktime);
> +extern void drm_send_vblank_event(struct drm_device *dev, int crtc,
> +				     struct drm_pending_vblank_event *e);
>  extern bool drm_handle_vblank(struct drm_device *dev, int crtc);
>  extern int drm_vblank_get(struct drm_device *dev, int crtc);
>  extern void drm_vblank_put(struct drm_device *dev, int crtc);
> --