On Thu, Nov 28, 2019 at 05:14:51PM +0100, Rafael J. Wysocki wrote:
On Thu, Nov 28, 2019 at 5:03 PM Thierry Reding thierry.reding@gmail.com wrote:
From: Thierry Reding treding@nvidia.com
Currently the driver PM core will automatically acquire a runtime PM reference for devices before system sleep is entered. This is needed to avoid potential issues related to devices' parents getting put to runtime suspend at the wrong time and causing problems with their children.
Not only for that.
In some cases drivers are carefully written to avoid such issues and the default behaviour can be changed to allow runtime PM to operate regularly during system sleep.
But this change breaks quite a few assumptions in the core too, so no, it can't be made.
Anything in particular that I can look at? I'm not seeing any issues when I test this, which could of course mean that I'm just getting lucky.
One thing that irritated me is that I think this used to work. I do recall testing suspend/resume a few years ago and devices would get properly runtime suspended/resumed. I did some digging but couldn't find anything that would have had an impact on this.
Given that this is completely opt-in feature, why are you categorically NAK'ing this?
Is there some other alternative that I can look into?
Thierry