> -----Original Message----- > From: Michel Dänzer [mailto:mic...@daenzer.net] > Sent: Thursday, September 01, 2016 9:47 PM > To: Alex Deucher > Cc: amd-gfx list; Deucher, Alexander > Subject: Re: [PATCH 03/10] drm/amdgpu: handle runtime pm in fbcon > > On 02/09/16 05:44 AM, Alex Deucher wrote: > > On Wed, Aug 31, 2016 at 9:04 PM, Michel Dänzer <mic...@daenzer.net> > wrote: > >> On 01/09/16 07:08 AM, Alex Deucher wrote: > >>> Ported from nouveau. > >>> > >>> Signed-off-by: Alex Deucher <alexander.deuc...@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. > > It decreases dev->power.usage_count, and my worry was that > pm_runtime_get_sync might not have increased it when it returns an > error. But it turns out that it does increase it unconditionally. > > > However, I'm afraid there seems to be another related problem: If > amdgpufb_open returns an error, amdgpufb_release won't be called > AFAICT. > In which case amdgpufb_open needs to call pm_runtime_put_autosuspend > in > the error case, or the GPU can never power off after that.
Good point. I'll fix that up. Alex > > > -- > Earthling Michel Dänzer | http://www.amd.com > Libre software enthusiast | Mesa and X developer _______________________________________________ amd-gfx mailing list amd-gfx@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/amd-gfx
