On Mon, 14 Jan 2019 18:51:31 +0100, Chris Wilson wrote:
Quoting Takashi Iwai (2019-01-14 17:46:57)
On Mon, 14 Jan 2019 18:37:53 +0100, Chris Wilson wrote:
Just in case the audio linkage is swapped between components during the runtime pm sequence, we need to protect the rpm tracking with a mutex.
It's not clear to me how does this happens. Could you elaborate a bit more the scenario?
The code is written such that multiple bits within display_power_status can be set and cleared simultaneously. There was no serialisation mentioned in the routine, so I was fearful that the display_power_active here was being accessed concurrently -- and if that was explaining why snd/hda appears to be leaking the runtime pm (or at least is holding on to the wakeref longer than igt expects, > 10s).
Aha, and does patch actually "fix" the issue...?
It's a simple mutex addition, so no big show, and I'm fine with it, but just wonder whether it really helped.
thanks,
Takashi