Re: [PATCH v1] driver core: Fix suspend/resume order issue with deferred probe

[Saravana Kannan]

On Fri, Jul 10, 2020 at 6:21 AM Greg Kroah-Hartman
<gregkh@xxxxxxxxxxxxxxxxxxx> wrote:
>
> On Tue, Jun 30, 2020 at 10:11:01AM -0700, Saravana Kannan wrote:
> > I already have a patch to avoid deferred probe during batch fwnode
> > parsing. I'm trying to do a few more tests before I send it out. So,
> > it'd be nice if we don't revert it right now and give me some time to
> > finish testing.
>
> So this series is no longer needed given your other series that I just
> took?

This series is no longer needed to fix the issue with fw_devlink
optimization that Geert was seeing. The other series you pulled in
takes care of Geert's issue.

But deferred probe can still break suspend/resume ordering (example
mentioned in the commit text). So I think we should fix that (version
X of this patch).

Rafael was concerned about some of the extra work v1 will cause for
cases that work fine today. So, we need to find a compromise where we
can fix the issue and optimize the fix as much as possible.

One optimization we can do is to call device_pm_move_to_tail(dev) in
really_probe() only after deferred probe is triggered (as in the
thread gets to run) for the first time. Until then, really_probe()
wouldn't have to call device_pm_move_to_tail(dev);

-Saravana