From: Greg KH <greg@kroah.com>
To: linux-hotplug@vger.kernel.org
Subject: Re: [PATCH] USB hotplug race
Date: Fri, 26 Mar 2004 23:05:32 +0000 [thread overview]
Message-ID: <20040326230532.GF31372@kroah.com> (raw)
In-Reply-To: <20040317142717.GA14149@pasky.ji.cz>
On Wed, Mar 17, 2004 at 03:27:17PM +0100, Petr Baudis wrote:
> Hello,
>
> so I finally upgraded from 2.4 to 2.6 (2.6.4), and one of the few
> problems I've hit is hotplug. Basically, when I start up hotplug while
> my Zaurus is plugged, everything works fine and usbnet gets loaded,
> however when I plug Zaurus after hotplug was loaded, it trashes the
> event.
>
> 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 :)
thanks,
greg k-h
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next prev parent reply other threads:[~2004-03-26 23:05 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 [this message]
2004-03-27 0:05 ` Oliver Neukum
2004-03-27 0:12 ` Greg KH
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