[PATCH 03/10] drm/amdgpu: handle runtime pm in fbcon

[Alex Deucher]

On Wed, Aug 31, 2016 at 9:04 PM, Michel Dänzer <michel at daenzer.net> wrote:
> On 01/09/16 07:08 AM, Alex Deucher wrote:
>> Ported from nouveau.
>>
>> Signed-off-by: Alex Deucher <alexander.deucher at amd.com>
>
> [...]
>
>> +static int
>> +amdgpufb_open(struct fb_info *info, int user)
>> +{
>> +     struct amdgpu_fbdev *rfbdev = info->par;
>> +     struct amdgpu_device *adev = rfbdev->adev;
>> +     int ret = pm_runtime_get_sync(adev->ddev->dev);
>> +     if (ret < 0 && ret != -EACCES)
>> +             return ret;
>> +     return 0;
>> +}
>> +
>> +static int
>> +amdgpufb_release(struct fb_info *info, int user)
>> +{
>> +     struct amdgpu_fbdev *rfbdev = info->par;
>> +     struct amdgpu_device *adev = rfbdev->adev;
>> +
>> +     pm_runtime_mark_last_busy(adev->ddev->dev);
>> +     pm_runtime_put_autosuspend(adev->ddev->dev);
>> +     return 0;
>> +}
>
> If pm_runtime_get_sync returns -EACCES, won't there be an imbalance with
> the pm_runtime_put_autosuspend call, which might result in the GPU
> powering off even when there's something else which is supposed to keep
> it on?
>
> Same for patch 8.

pm_runtime_get_sync only returns -EACCES when runtime pm has been
disabled in which case the GPU is on and pm_runtime_put_autosuspend
won't do anything.

Alex

>
>
> --
> Earthling Michel Dänzer               |               http://www.amd.com
> Libre software enthusiast             |             Mesa and X developer