Re: Hotplug events vs proc - timing

[Marcelo Ricardo Leitner <mrl@conectiva.com.br>]

On Wed Jun 02, 2004 at 13:36:09 -0400, Bill Nottingham wrote:
> Greg KH (greg@kroah.com) said: 
> > On Tue, Jun 01, 2004 at 01:32:22PM -0600, Ivan Gyurdiev wrote:
> > > Fedora's updfstab tool (part of kudzu) is trigged by hotplug to 
> > > add/remove things from fstab, such as my Fujifilm Digital Camera 
> > > (usb-storage, scsi emulation). However... it reads /proc/scsi/scsi, and 
> > > doesn't work as it should because it's triggered before /proc/scsi/scsi 
> > > is updated most of the time. Where is the bug, and how should this race 
> > > be corrected?
> > 
> > The race should be fixed by having the hotplug script wait around for
> > the proc file to show up.
> 
> Hm, as I was thinking, the hotplug event is triggered by the USB
> insertion; what's really needed for updfstab is that it gets
> run triggered on the *scsi* device creation. Or is this the proc
> file you're referring too?
---end quoted text---

What about having something like:

while [ ! -f /proc/cmdline ]; do
        sleep 1;
done

at /etc/hotplug/usb.agent?
But be careful, if your proc doesn't show it, this process would stay alive
forever. Putting a timeout no X retries on it doesn't seem to be a bad idea.
Also, note that /proc can be mounted, but not /proc/bus/usb.

Or ignore the signal and coldplug it. :)

Best regards,
-- 
Marcelo Ricardo Leitner <mrl@conectiva.com.br>


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