On Thu, 2020-04-16 at 09:04 +0200, Takashi Iwai wrote: > On Thu, 16 Apr 2020 07:52:45 +0200, > Sridharan, Ranjani wrote: > > > > Hi Takashi, > > > > While working on implementing the probes features in SOF using a > > separate card > > for the probe DAI links, I noticed that calling > > snd_soc_register_card() > > results in > > incrementing the usage_count for the device that registers the card > > by 2 and > > it is not decremented until the card is freed. > > > > Is this the expected behaviour? Typically, we register a separate > > platform > > device for the Intel machines which in turn register the card and > > none of them > > ever enable runtime PM. So this has no impact on the parent > > device's runtime > > PM status. > > > > I'd like to avoid creating a separate platform device just to > > register the > > card if possible while also enabling runtime PM . But when I do > > this today, > > the device cannot enter runtime suspend at all. Could you please > > shed some > > light on this? > > It's not clear how you see the things. Which device are you looking > at? Typically a card object points to two different devices, one is > the real device that the chip belongs to (card->dev), and another the > own device object for managing the device files (card.card_dev). > And in general, snd_soc_card_register() or snd_card_register() don't > manipulate the runtime PM stuff by itself at all. Its the card->dev that I am looking at. This is the device that calls devm_snd_soc_register_card(). In my tests, the usage_count for this device is 0 before calling devm_snd_soc_register_card and it is 2 after the card registration is complete. Thanks, Ranjani
