On Fri 07 Feb 2020 at 11:53:12 -0500, Michael Stone wrote: > On Fri, Feb 07, 2020 at 03:36:55PM +0000, Brian wrote: > > On Fri 07 Feb 2020 at 10:25:22 -0500, Michael Stone wrote: > > > > > On Fri, Feb 07, 2020 at 03:05:31PM +0000, Brian wrote: > > > > On Fri 07 Feb 2020 at 09:37:17 -0500, Michael Stone wrote: > > > > > > > > > On Fri, Feb 07, 2020 at 10:36:11AM +0800, kaye n wrote: > > > > > > Hello Friends! > > > > > > > > > > > > I'm running: > > > > > > Kernel: 4.19.0-6-amd64 x86_64 > > > > > > bits: 64 > > > > > > Desktop: Xfce 4.12.4 > > > > > > Distro: Debian GNU/Linux 10 (buster) > > > > > > > > > > > > My printer is an Epson L220. It's connected to my laptop's USB > > > > > > port. > > > > > > > > > > > > The command lsusb shows: > > > > > > Bus 002 Device 003: ID 04b8:08d1 Seiko Epson Corp. > > > > > > > > > > > > Therefore in the file, /etc/sane.d/epkowa.conf > > > > > > I added this line: > > > > > > usb 0x04b8 0x08d1 > > > > > > > > > > > > The printer can print just fine, but ImageScan and XSane would not > > > > > > run. > > > > > > > > > > > > ImageScan says: > > > > > > Could not send command to scanner. Check the scanner's status. > > > > > > > > > > > > XSane says: > > > > > > Failed to open device 'epkowa:usb:002:003': > > > > > > Access to resource has been denied. > > > > > > > > > > > > Thank you for your time! > > > > > > > > > > This smells like a permission problem. In your example above the > > > > > scanner is > > > > > on bus 002 device 003. (It may change as you unplug and replug usb > > > > > devices, > > > > > so check with lsusb and change the numbers below as needed.) You can > > > > > see the > > > > > permissions for that device with: > > > > > ls -l /dev/bus/usb/002/003 > > > > > If it comes back with something that starts with: > > > > > crw-rw-r-- 1 root root > > > > > then it's writable only by root. A working configuration would have > > > > > either > > > > > crw-rw-rw- 1 root root > > > > > or would having your username or a group that you're in rather than > > > > > root, or > > > > > would look like > > > > > crw-rw-r--+ 1 root root > > > > > indicating an ACL which you can see via getfacl /dev/bus/usb/002/003 > > > > > (there would be a line with your username in the default libsane > > > > > configuration). > > > > > > > > > > Assuming the permissions look like they might be the problem, you can > > > > > confirm that by running > > > > > chmod o+w /dev/bus/usb/002/003 > > > > > to make the file world writable (for testing only; it isn't > > > > > permantent if > > > > > the scanner is unplugged or the system rebooted). If xsane works, > > > > > you've > > > > > found the problem. If that's the case, the next step is probably to > > > > > update > > > > > the udev configuration. If not, on to the next guess. :) > > > > > > > > Permisions on the USB bus are managed by an ACL. > > > > > > > > https://wiki.debian.org/Scanner > > > > > > Yes, that's why I mentioned the ACL. :) But, it hasn't always been that > > > way > > > and it's not the only way that will actually work...hence the other > > > possibilities. > > > > It is the way it is now on unstable/buser/stretch. What is in the past > > is in the past. No user should have to mess about with permissions or > > be in the scanner group to have permission to use a USB scanner. If it > > is a route that is thought to be necessary, there is something wrong > > with the user's setup or it is a bug. > > There's nothing wrong with the user's setup if they have a configuration > (possibly older) that sets permissions in a way that works even if it isn't > the current default.
Like protocols, everyone can have their own set of defaults on buster. In which case, they can sort their own problems out. :) > I'd rather show someone how they can identify whether > the permissions are a problem than have them waste their time > changing things if it isn't even an issue. YMMV. Indeed. The wiki attempts to do that for a buster user such as the OP. sane-find-scanner is also a useful tool. -- Brian.
