[sane-devel] Hotplug and udev files created automatically now,
m. allan noah
anoah at pfeiffer.edu
Tue May 2 17:45:34 UTC 2006
SANE_DEBUG_SANEI_USB=255 scanimage -L
then look thru that output. do you see a line like this:
[sanei_usb] sanei_usb_init: Looking for kernel scanner devices
what comes immediately after that?
On Tue, 2 May 2006, Peter Christy wrote:
> On Tuesday 02 May 2006 17:40, m. allan noah wrote:
>> i am confused by this- first you say that you need sane to look under
>> /sys or /dev for devices, then you say that you have to alter permissions
>> to get it working. which is it?
> udev mounts the usbscanner under /sys In my case, under /sys/bus/usb/ and then
> a randomly variable point. However, given the relevant vendor and product
> IDs, it will automatically create a symlink in /dev and set all the relevant
> So for example, I can make it produce a /dev/usbscanner symlink that will
> always point to the scanner, wherever it may have appeared on
> the /sys/bus/usb/ directory, and have the right permissions.
> However, sane appears to be looking for the scanner
> under /proc/bus/usb/whatever, which udev cannot easily (as far as I can see)
> set the permissions. As in the /sys file system, it seems to be somewhat
> random where it pops up, from one reboot to the next, although the location
> does correspond to the location under /sys.
> Even hotplug was incapable of setting the permissions automatically, because
> although my scanner always appeared as /proc/bus/usb/002/002, hotplug
> *always* tried to set the permissions for /proc/bus /usb/001/002! This was a
> bug in hotplug that never got fixed! I bypassed it by adding
> chown root:users /proc/bus/usb/002/002
> chmod 0660 /proc/bus/usb/002/002
> to my rc.local file. However, this only works if the scanner always appears
> on /proc/bus/usb/002/002 Under udev alone, it doesn't. As often as not it
> appears as /proc/bus/usb/001/003 or even something else!
> I need to find some way of making sane use /dev/usbscanner to access the
> scanner rather than /proc/bus/usb/whatever. My understanding is that this is
> a very old way of doing things that only works with kernel scanner modules.
> Certainly my initial attempts in this area have met with total failure!
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