[sane-devel] XSANE ... hotplug & 'mail image' probs.

Bertrik Sikken bertrik@zonnet.nl
Thu, 16 Sep 2004 08:48:26 +0200

Adam Bogacki wrote:
> Having got XSANE working, I have two problems.
> (1) I installed hotplug with permissions to allow user access after 
> hotplugging.
> That works. However a problem arises when using Applications -> Graphics 
> -> XSane as user,
> XSane tells me 'no devices available', but on pulling out and 
> re-inserting the scanner
> plug it works. How does one alter permissions to allow the above to work 
> without
> disabling hotplug ?

In the 2.6.x range of kernels there is a weird issue (=bug?), i.e.
there is a race between the hotplug event and the creation of the
libusb 'device file' (in /proc/bus/usb).
The libusbscanner hotplug script does not take this into account
so it may happen sometimes that the script tries to update permission
for a file that doesn't exist yet.
As far as I know, this race will be looked at in the next kernel
series, but for now you can use a dirty hack like a 'sleep 1'
at the top of the hotplug script.