On Thu, Dec 13, 2018 at 5:25 PM Daniel Vetter <daniel.vet...@ffwll.ch> wrote: > > On Thu, Dec 13, 2018 at 5:18 PM Rafael J. Wysocki <raf...@kernel.org> wrote: > > > > On Thu, Dec 13, 2018 at 1:36 PM Daniel Vetter <daniel.vet...@ffwll.ch> > > wrote:
[cut] > > > I can do the old code exactly, but afaict the non-NULL parent just > > > takes care of the parent bus locking for us, instead of hand-rolling > > > it in the caller. But if I missed something, I can easily undo that > > > part. > > > > It is different if device links are present, but I'm not worried about > > that case honestly. :-) > > What would change with device links? We have some cleanup plans to > remove our usage for early/late s/r hooks with a device link, to make > sure i915 resumes before snd_hda_intel. Digging more into the code I > only see the temporary dropping of the parent's device_lock, but I > have no idea what that even implies ... That's just it (which is why I said I was not worried). Running device_links_unbind_consumers() with the parent lock held may deadlock if another child of the same parent also is a consumer of the current device (which really is a corner case), but the current code has this problem - it goes away with your change. But dev->bus->need_parent_lock checks are missing in there AFAICS, let me cut a patch to fix that. Cheers, Rafael
