what are the perms on the actual /proc/bus/usb/XXX/YYY file? allan
On 1/30/07, Karen Pease <[email protected]> wrote: > Is it possible to have non-root users scan from the MP530? I've been spinning > my gears just to get the scanner to work at all as root, and finally managed > to only by installing the CVS version of the backend and fiddling around with > it. However, I can't seem to get a common user to have access to the > scanner. > > First, what root sees. Lets just do a test. > > [root@daughtersoftiresias sane-backends]# scanimage -L > [sanei_debug] Setting debug level of pixma to 10. > [pixma] pixma version 0.12.2 > device `v4l:/dev/video0' is a Noname BT848 video ( *** UNKNOWN/GENER virtual > device > device `pixma:04A91712_114A42' is a CANON Canon PIXMA MP530 multi-function > peripheral > [root@daughtersoftiresias sane-backends]# scanimage -d pixma:04A91712_114A42 > -n > [sanei_debug] Setting debug level of pixma to 10. > [pixma] pixma version 0.12.2 > [pixma] pixma_open(): Canon PIXMA MP530 > [pixma] pixma_close(): Canon PIXMA MP530 > [root@daughtersoftiresias sane-backends]# > > Success. Now, for a mere mortal (with the same SANE-related > debug/experimental environmental variables): > > [meme@daughtersoftiresias ~]$ scanimage -L > [sanei_debug] Setting debug level of pixma to 10. > [pixma] pixma version 0.12.2 > device `v4l:/dev/video0' is a Noname BT848 video ( *** UNKNOWN/GENER virtual > device > device `pixma:04A91712' is a CANON Canon PIXMA MP530 multi-function peripheral > [meme@daughtersoftiresias ~]$ scanimage -d pixma:04A91712 -n > [sanei_debug] Setting debug level of pixma to 10. > [pixma] pixma version 0.12.2 > [pixma] pixma_open(): Canon PIXMA MP530 > [pixma] pixma_connect() failed EACCES > [pixma] pixma_open() failed EACCES > [pixma] pixma_close(): Canon PIXMA MP530 > scanimage: open of device pixma:04A91712 failed: Access to resource has been > denied > [meme@daughtersoftiresias ~]$ scanimage -d pixma:04A91712_114A42 -n > [sanei_debug] Setting debug level of pixma to 10. > [pixma] pixma version 0.12.2 > scanimage: open of device pixma:04A91712_114A42 failed: Invalid argument > [meme@daughtersoftiresias ~]$ > > The first thing to notice is that the regular user doesn't see the same device > name as root from scanimage -L: they see a name that's missing the serial, > thus an improperly formatted pixma device name, as far as I can tell. When I > give that device, we get an "access denied", even though I've set > my /proc/bus/usb wide open. When I try the proper name that root is given > (but meme is not), I get an invalid argument -- the same as I'd get if I > typed -d pixma:qwijibo or -d pixma:ThisIsNotAValidDevice. > > So, why does it omit the serial? Well, I think I've got that one figured out. > From sane-find-scanner -v -v: First, as root: > > trying libusb: > > <device descriptor of 0x04a9/0x1712 at 002:007 (Canon MP530)> > bLength 18 > bDescriptorType 1 > bcdUSB 2.00 > bDeviceClass 0 > bDeviceSubClass 0 > bDeviceProtocol 0 > bMaxPacketSize0 64 > idVendor 0x04A9 > idProduct 0x1712 > bcdDevice 1.05 > iManufacturer 1 (Canon) > iProduct 2 (MP530) > iSerialNumber 3 (114A42) > bNumConfigurations 1 > <configuration 0> > ... > > Now, as meme: > > trying libusb: > > <device descriptor of 0x04a9/0x1712 at 002:007> > bLength 18 > bDescriptorType 1 > bcdUSB 2.00 > bDeviceClass 0 > bDeviceSubClass 0 > bDeviceProtocol 0 > bMaxPacketSize0 64 > idVendor 0x04A9 > idProduct 0x1712 > bcdDevice 1.05 > iManufacturer 1 ((null)) > iProduct 2 ((null)) > iSerialNumber 3 ((null)) > bNumConfigurations 1 > <configuration 0> > > Meme seems unable to get iSerialNumber -- but it can get idVendor and > idProduct, and thus ultimately determine what kind of scanner we're dealing > with. The same thing happens with lsusb -v; root can see the serial number, > while meme can't. > > Does this look like what's causing the problem to you? Can you think of a way > to work around it? My ultimate goal is to be able to have users just start > up gimp and be able to scan, but as it stands, that's not an option. Which > is a shame, because I specifically picked the MP530 because all of its > features were reported as working well in Linux. > > Thanks! > > - Karen > > > -- > sane-devel mailing list: [email protected] > http://lists.alioth.debian.org/mailman/listinfo/sane-devel > Unsubscribe: Send mail with subject "unsubscribe your_password" > to [email protected] > -- "The truth is an offense, but not a sin"
