Messages in this thread | | | Date | Mon, 19 May 2014 15:53:58 -0400 (EDT) | From | Alan Stern <> | Subject | Re: [RFC][PATCH 2/3] PM / sleep: Mechanism to avoid resuming runtime-suspended devices unnecessarily |
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On Mon, 19 May 2014, Jacob Pan wrote:
> > Wouldn't that go a bit too far? It seems to be based on the > > assumption that all devices having no ->prepare() callback can be > > safely left in runtime suspend over a system suspend/resume cycle, > > but is that assumption actually satisfied for all such devices? > > > yes, I agree it is risky though i don't see problems with my limited > testing. But on the other side, it is too strict. > I also tried adding .prepare( return 1;) to usb_ep_device_type pm ops, > that didn't work either. The reason is that ep devices don't support > runtime pm (disable_depth > 0). I think in this case ignore_children > flag should be the right indicator to ignore pm_runtime_suspended()?
Maybe it would be better to add a new flag that means "This is a virtual device and the PM core can ignore it completely".
Alan Stern
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