[PATCH 2/6] drm/exynos: track vblank events on a per crtc basis

[Daniel Stone]

Hi,

On 23 January 2015 at 12:42, Gustavo Padovan <gustavo at padovan.org> wrote:
>  void exynos_drm_crtc_finish_pageflip(struct drm_device *dev, int pipe)
>  {
>         struct exynos_drm_private *dev_priv = dev->dev_private;
> -       struct drm_pending_vblank_event *e, *t;
>         struct drm_crtc *drm_crtc = dev_priv->crtc[pipe];
>         struct exynos_drm_crtc *exynos_crtc = to_exynos_crtc(drm_crtc);
> -       unsigned long flags;
>
> -       spin_lock_irqsave(&dev->event_lock, flags);
> +       if (exynos_crtc->event) {
>
> -       list_for_each_entry_safe(e, t, &dev_priv->pageflip_event_list,
> -                       base.link) {
> -               /* if event's pipe isn't same as crtc then ignore it. */
> -               if (pipe != e->pipe)
> -                       continue;
> -
> -               list_del(&e->base.link);
> -               drm_send_vblank_event(dev, -1, e);
> +               spin_lock_irq(&dev->event_lock);
> +               drm_send_vblank_event(dev, -1, exynos_crtc->event);
>                 drm_vblank_put(dev, pipe);
> -               atomic_set(&exynos_crtc->pending_flip, 0);
>                 wake_up(&exynos_crtc->pending_flip_queue);
> -       }
> +               spin_unlock_irq(&dev->event_lock);
>
> -       spin_unlock_irqrestore(&dev->event_lock, flags);
> +               exynos_crtc->event = NULL;
> +       }
>  }

Doesn't this need to hold the CRTC lock to not race with, e.g, the
page_flip caller? This gets called from IRQ context though, so might
need conversion to soft-IRQ to do so, or another per-CRTC spinlock
just to protect the event.

Cheers,
Daniel