On Tue, 2015-05-12 at 08:22 +0200, Oliver Neukum wrote:
> On Mon, 2015-05-11 at 13:58 -0500, Peter Berger wrote:
> > On Mon, 2015-05-11 at 11:44 -0400, Don Zickus wrote:
...
> >
> > /* Since usb-serial unbinds and reprobes on resume, the re-initialization
> > * (including re-scheduling heartbeat_task) is handled by edge_startup().
> > */
> >
> > Is that sufficient? Should I add something more or move it elsewhere?
>
> Is this universally true? It is true that most systems cut power
> in S3. This will lead to a reprobe. But I have a few systems which
> can keep ports powered. In those cases it looks to me like usbserial
> will do a normal suspend/resume cycle.
>
> Regards
> Oliver
>
>
Hi Oliver:
Your comment sent me digging deeper. I was under the (false) impression
that the reprobes were universal since all my tests -- even those on a
system that maintains USB bus power during S3 -- led to a reprobe. But
it turns out that while there are a number of conditions that can lead
to reprobes (for example, three such conditions are checked for in
uhci_check_and_reset_hc()) it's not necessarily universal.
I just sent out a v3 patchset which reschedules the heartbeats in
edge_resume() for those systems that do not reprobe on resume.
Thanks again for your insightful comments.
--Peter
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