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

[PrasannaKumar Muralidharan]

Hi Ville,

On 12 October 2017 at 22:52, Ville Syrjälä
<ville.syrjala at linux.intel.com> wrote:
> 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.

CI just told me this. I will keep this in mind even for simple patches.

>>       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