[Intel-gfx] [RFC] drm: drm_vblank_cleanup: WARN when refcount is more than 0

[Ville Syrjälä]

On Thu, Oct 12, 2017 at 10:30:06PM +0530, PrasannaKumar Muralidharan wrote:
> Warn when refcount > 0 in drm_vblank_cleanup.
> 
> In i915 driver unload drm_vblank_get is added to test whether this patch
> is working. This will be removed once the patch gets tested.
> 
> Signed-off-by: PrasannaKumar Muralidharan <prasannatsmkumar at gmail.com>
> ---
>  drivers/gpu/drm/drm_vblank.c    | 2 ++
>  drivers/gpu/drm/i915/i915_drv.c | 1 +
>  2 files changed, 3 insertions(+)
> 
> diff --git a/drivers/gpu/drm/drm_vblank.c b/drivers/gpu/drm/drm_vblank.c
> index 70f2b95..2a6630a 100644
> --- a/drivers/gpu/drm/drm_vblank.c
> +++ b/drivers/gpu/drm/drm_vblank.c
> @@ -402,6 +402,8 @@ void drm_vblank_cleanup(struct drm_device *dev)
>  	if (dev->num_crtcs == 0)
>  		return;
>  
> +	WARN_ON(atomic_read(&vblank->refcount) > 0);
> +

That won't even compile. Always at least compile + sparse check +
checkpatch your stuff, otherwise you're just going to be wasting
other people's or the CI systems's time.

>  	for (pipe = 0; pipe < dev->num_crtcs; pipe++) {
>  		struct drm_vblank_crtc *vblank = &dev->vblank[pipe];
>  
> diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c
> index 9f45cfe..c7a93a9 100644
> --- a/drivers/gpu/drm/i915/i915_drv.c
> +++ b/drivers/gpu/drm/i915/i915_drv.c
> @@ -1373,6 +1373,7 @@ void i915_driver_unload(struct drm_device *dev)
>  	struct drm_i915_private *dev_priv = to_i915(dev);
>  	struct pci_dev *pdev = dev_priv->drm.pdev;
>  
> +	drm_vblank_get(dev_priv, 0);
>  	i915_driver_unregister(dev_priv);
>  
>  	if (i915_gem_suspend(dev_priv))
> -- 
> 2.10.0
> 
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-- 
Ville Syrjälä
Intel OTC