On Fri, Jun 17, 2016 at 06:54:48PM +0100, Chris Wilson wrote:
> During cleanup we have to synchronise with the async task we are using
> to initialise and register our fbdev. Currently, we are using a full
> synchronisation on the global domain, but we can restrict this to just
> synchronising up to our task if we remember our cookie.
> 
> v2: async_synchronize_cookie() takes an exclusive upper bound, to
> synchronize with our task we have to pass in the next cookie.
> v3: Drop premature disregarding of the active cookie (we need to wait
> until the task is complete before continuing in the teardown).
> 
> Signed-off-by: Chris Wilson <[email protected]>
> Cc: Lukas Wunner <[email protected]>
> ---
>  drivers/gpu/drm/i915/intel_drv.h   |  1 +
>  drivers/gpu/drm/i915/intel_fbdev.c | 29 ++++++++++++++++-------------
>  2 files changed, 17 insertions(+), 13 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/intel_drv.h 
> b/drivers/gpu/drm/i915/intel_drv.h
> index 0c1dc9bae170..b657ddd2d078 100644
> --- a/drivers/gpu/drm/i915/intel_drv.h
> +++ b/drivers/gpu/drm/i915/intel_drv.h
> @@ -159,6 +159,7 @@ struct intel_framebuffer {
>  struct intel_fbdev {
>       struct drm_fb_helper helper;
>       struct intel_framebuffer *fb;
> +     async_cookie_t cookie;
>       int preferred_bpp;
>  };
>  
> diff --git a/drivers/gpu/drm/i915/intel_fbdev.c 
> b/drivers/gpu/drm/i915/intel_fbdev.c
> index 4babefc51eb2..638e420a59cb 100644
> --- a/drivers/gpu/drm/i915/intel_fbdev.c
> +++ b/drivers/gpu/drm/i915/intel_fbdev.c
> @@ -538,8 +538,7 @@ static const struct drm_fb_helper_funcs 
> intel_fb_helper_funcs = {
>       .fb_probe = intelfb_create,
>  };
>  
> -static void intel_fbdev_destroy(struct drm_device *dev,
> -                             struct intel_fbdev *ifbdev)
> +static void intel_fbdev_destroy(struct intel_fbdev *ifbdev)
>  {
>       /* We rely on the object-free to release the VMA pinning for
>        * the info->screen_base mmaping. Leaking the VMA is simpler than
> @@ -552,12 +551,14 @@ static void intel_fbdev_destroy(struct drm_device *dev,
>       drm_fb_helper_fini(&ifbdev->helper);
>  
>       if (ifbdev->fb) {
> -             mutex_lock(&dev->struct_mutex);
> +             mutex_lock(&ifbdev->helper.dev->struct_mutex);
>               intel_unpin_fb_obj(&ifbdev->fb->base, BIT(DRM_ROTATE_0));
> -             mutex_unlock(&dev->struct_mutex);
> +             mutex_unlock(&ifbdev->helper.dev->struct_mutex);
>  
>               drm_framebuffer_remove(&ifbdev->fb->base);
>       }
> +
> +     kfree(ifbdev);
>  }
>  
>  /*
> @@ -732,32 +733,34 @@ int intel_fbdev_init(struct drm_device *dev)
>  
>  static void intel_fbdev_initial_config(void *data, async_cookie_t cookie)
>  {
> -     struct drm_i915_private *dev_priv = data;
> -     struct intel_fbdev *ifbdev = dev_priv->fbdev;
> +     struct intel_fbdev *ifbdev = data;
>  
>       /* Due to peculiar init order wrt to hpd handling this is separate. */
>       if (drm_fb_helper_initial_config(&ifbdev->helper,
>                                        ifbdev->preferred_bpp))
> -             intel_fbdev_fini(dev_priv->dev);
> +             intel_fbdev_fini(ifbdev->helper.dev);
>  }
>  
>  void intel_fbdev_initial_config_async(struct drm_device *dev)
>  {
> -     async_schedule(intel_fbdev_initial_config, to_i915(dev));
> +     struct intel_fbdev *ifbdev = to_i915(dev)->fbdev;
> +
> +     ifbdev->cookie = async_schedule(intel_fbdev_initial_config, ifbdev);
>  }
>  
>  void intel_fbdev_fini(struct drm_device *dev)
>  {
>       struct drm_i915_private *dev_priv = dev->dev_private;
> -     if (!dev_priv->fbdev)
> +     struct intel_fbdev *ifbdev = dev_priv->fbdev;
> +
> +     if (!ifbdev)
>               return;
>  
>       flush_work(&dev_priv->fbdev_suspend_work);
> +     if (ifbdev->cookie && !current_is_async())
> +             async_synchronize_cookie(ifbdev->cookie + 1);

First I went like wtf about the cookie+1, but the main use case for this
function (or intended use-case at least) is to synchronize with everything
before your own async task when you register. To uphold deterministic dev
node ordering ...

Needs a comment in the code imo, this is too suprising:

        /* Only synchronizes with all _preceeding_ async tasks, hence + 1 */

Or whatever you feel like.


>  
> -     if (!current_is_async())
> -             async_synchronize_full();
> -     intel_fbdev_destroy(dev, dev_priv->fbdev);
> -     kfree(dev_priv->fbdev);
> +     intel_fbdev_destroy(ifbdev);

"While at it simplify fbdev functions paramaters." ;-)

With the bikesheds addressed:

Reviewed-by: Daniel Vetter <[email protected]>

>       dev_priv->fbdev = NULL;
>  }
>  
> -- 
> 2.8.1
> 
> _______________________________________________
> Intel-gfx mailing list
> [email protected]
> https://lists.freedesktop.org/mailman/listinfo/intel-gfx

-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch
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