* Alan Stern <stern@xxxxxxxxxxxxxxxxxxx> [160330 12:26]:
> On Wed, 30 Mar 2016, Ivaylo Dimitrov wrote:
>
> > >>> seems to be created twice :). Maybe the problem is that the first time
> > >>> musb-hdrc is probed it fails with -EPROBE_DEFER, however that failure is
> > >>> after gadget drivers got loaded and noone unloads them.
> > >>
> > >> gadget drivers will get added to a pending list, then later they'll
> > >> bind. But they shouldn't bind() twice, unless there are multiple
> > >> interfaces for them.
> > >>
> > >
> > > Well, then it seems we have problem, as the 2 unbind() calls are with
> > > one and the same "common" pointer (again, from memory).
> > >
> > >>> Just some wild guesses based on my memories as I've lost the logs (power
> > >>> outage). For sure I can recreate them if needed.
> > >>
> > >> okay.
> > >
> > > I will redo dump_stack() and printks and will provide logs as soon as I
> > > have some time, so to stop counting on my memories.
> > >
> >
> > Please find attached the relevant logs. It really seems that g_nokia is
> > probed twice, with all the gadgets in it created two times. I am
> > starting to suspect 855ed04a3758b205e84b269f92d26ab36ed8e2f7 ("usb:
> > gadget: udc-core: independent registration of gadgets and gadget
> > drivers") has something to do with the problem, though reverting it
> > resulted in g_nokia not being probed at all :)
>
> The problem is not caused by nokia_bind() getting called twice. The
> log clearly shows that nokia_bind() is called only once, but it calls
> usb_add_config() from two different places:
>
> Jan 1 02:00:10 Nokia-N900 kernel: [ 8.002838] [<c040c5b4>] (usb_add_config) from [<c041b274>] (nokia_bind+0x160/0x2f0)
> Jan 1 02:00:10 Nokia-N900 kernel: [ 8.014526] [<c041b274>] (nokia_bind) from [<c040e128>] (composite_bind+0x68/0x1a0)
> ...
> Jan 1 02:00:10 Nokia-N900 kernel: [ 8.381286] [<c040c5b4>] (usb_add_config) from [<c041b28c>] (nokia_bind+0x178/0x2f0)
> Jan 1 02:00:10 Nokia-N900 kernel: [ 8.394348] [<c041b28c>] (nokia_bind) from [<c040e128>] (composite_bind+0x68/0x1a0)
>
> Everything else along the two pathways is the same, so this is where
> the multiple binds come from. And indeed, looking at the code in
> nokia_bind() you can see the two calls:
>
> /* finally register the configuration */
> status = usb_add_config(cdev, &nokia_config_500ma_driver,
> nokia_bind_config);
> if (status < 0)
> goto err_msg_luns;
>
> status = usb_add_config(cdev, &nokia_config_100ma_driver,
> nokia_bind_config);
>
> This isn't supposed to cause any problems. The two instances should
> never run at the same time, because they belong to different configs.
Maybe drivers/usb/gadget/legacy/ether.c suffers from a similar issue
as that's what I noticed the $subject problem with.
Regards,
Tony
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