From: Oliver Neukum <oliver@neukum.org>
To: linux-hotplug@vger.kernel.org
Subject: Re: [PATCH] USB hotplug race
Date: Sat, 27 Mar 2004 00:05:52 +0000 [thread overview]
Message-ID: <200403270105.52263.oliver@neukum.org> (raw)
In-Reply-To: <20040317142717.GA14149@pasky.ji.cz>
> > After populating the hotplug scripts with plethora of debug prints,
> > I've tracked it down to usb_convert_vars() - basically, immediatelly
> > after the USB device is plugged and the signal is already delivered to
> > hotplug, the sysfs tree isn't yet populated by all the relevant data
> > and only detach_state is present there - no bDeviceClass or so.
>
> Yes, it's quite easy to race the kernel with this. But how about
> putting the proper patch in by sitting and spinning until we see the
> file we are looking for (or erroring out after a time period.)
>
> That's much cleaner than always sleeping. On a SMP box, you usually
> never need to sleep :)
It seems to me the proper patch would be for the kernel to wait for
the creation of any files it refers to when generating a hotplug invocation.
Regards
Oliver
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next prev parent reply other threads:[~2004-03-27 0:05 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2004-03-17 14:27 [PATCH] USB hotplug race Petr Baudis
2004-03-26 23:05 ` Greg KH
2004-03-27 0:05 ` Oliver Neukum [this message]
2004-03-27 0:12 ` Greg KH
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