[RESEND AGAIN][PATCH] pcmcia: move unbind/rebind into dev_pm_ops.complete
chunkeey at googlemail.com
Mon Jul 9 19:07:26 EDT 2012
On Tuesday, July 10, 2012 01:01:31 AM Andrew Morton wrote:
> On Tue, 10 Jul 2012 00:54:54 +0200
> Christian Lamparter <chunkeey at googlemail.com> wrote:
> > On Monday, July 09, 2012 11:59:39 PM Andrew Morton wrote:
> > > On Fri, 6 Jul 2012 14:30:16 -0700
> > > Greg KH <gregkh at linuxfoundation.org> wrote:
> > >
> > > > On Fri, Jul 06, 2012 at 11:23:52PM +0200, Christian Lamparter wrote:
> > > > > The idea of moving rebind procedure into pm.complete
> > > > > was taken from the usb-subsystem, which has similar
> > > > > problems with reattaching devices during/after
> > > > > resume.
> > > > >
> > > > > Signed-off-by: Christian Lamparter <chunkeey at googlemail.com>
> > > > > ---
> > > > > To Greg:
> > > > >
> > > > > I have submitted this patch back in March and again in May.
> > > > > As far as I can tell it was neither rejected nor was it
> > > > > accepted into linux-pcmcia.git since. So I'm asking you,
> > > > > if you could take the patch instead... please.
> > > >
> > > > There is a PCMCIA "team" who should be taking these types of patches.
> > > > Why are they not doing so?
> > > >
> > >
> > > Things are pretty quiet in pcmcia world, but Dominik does appear to
> > > still be doing stuff.
> > >
> > > I sometimes queue PCMCIA patches for people, but not this one. The
> > > changelog is just junk. What does the patch do? Why does it do it?
> > > What problems does it solve? What are these mysterious "problems with
> > > reattaching devices" to which it refers? Useless...
> > >
> > Well, that can be improved, but it is a bit tricky.
> > AFAICT the usb subsystem dealt with pm in this commit:
> > "commit 5096aedcd2eb70fbea83f09281f97f9ec973d9de
> > Author: Alan Stern <stern at rowland.harvard.edu>
> > Date: Tue Aug 12 14:34:14 2008 -0400
> > USB: Don't rebind before "complete" callback
> > [...] We are not allowed to call drivers' probe routines during
> > a system sleep transition between the "prepare" and "complete"
> > callbacks, but that's exactly what we do when a driver doesn't
> > have full suspend/resume support. [...]"
> > And on the pcmcia subsystem we have this:
> > "commit 88b060d6c03fcb9e4d2018b4349954c4242a5c7f
> > Author: Dominik Brodowski <linux at dominikbrodowski.net>
> > Date: Sat Jan 2 14:14:23 2010 +0100
> > pcmcia: improve check for same card in slot after resume
> > During a suspend/resume cycle, an user may change the card in the
> > PCMCIA/CardBus slot. [...]
> > For CardBus devices, the PCI hotplug interface doesn't offer a "rescan"
> > facility which also _removes_ devices no longer to be found behind a
> > bridge. Therefore, remove and re-add all devices unconditionally."
> > Unfortunately, the "re-add" is currently done in the *pm resume* callback
> > (socket_late_resume), but according to "USB: Don't rebind..." is not
> > allowed to have it there, so the patch moves it into the *pm complete*
> > callback. The Documentation/power/* contains mostly informations for
> > drivers developers, but AFAICT it doesn't say much about the subsystem
> > to which the device is connected should behave, so there's a bit of a
> > "citing-gap".
> hm, it does seem a bit of a screwup.
> What's unclear to me is whether your patch fixes any observed runtime
> problems. Or adds any runtime problems, which looks to be a distinct
well, there is this bug
> > So, my question now: Would you accept the pcmcia patch if I add the
> > "USB: Don't rebind..." as a reference to why the re-add needs to be
> > done in complete? Or do you think that I should bug the pm people
> > (and Alan - since he wrote that it is "not allowed") in this case
> > so I can link their official answer to this patch?
> Well I could grab it and give it a little bit of testing in linux-next.
> But I'd be super-reluctant to send such a patch upstream without
> detailed input from Alan/Greg/Rafael/Dominik/etc.
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