well, the sane developers seem to be working on this as well: http://lists.alioth.debian.org/pipermail/sane-devel/2007-July/019680.html
quoted: > Hi, > > CONFIG_USB_SUSPEND, a Linux kernel option that makes the USB layer > automatically put USB devices to suspend state when they're not in > use, has exposed a number of bugs in pretty much all the USB > scanners. > > Upon being suspended, the scanners will usually do an unplug/plug > cycle instead of going into the suspended state - what really happens > in most cases is that the scanner resets himself, loosing its settings > and sometimes its firmware. Some scanners may react differently, > exposing more hardware bugs (eg. their USB interface may crash). > > Starting with Linux 2.6.22, two things have happened: > - a blacklist for the autosuspend feature, in which a lot of scanners > are being added, mainly by Oliver Neukum from what I've seen, has been > added. As of 2.6.22, the blacklist only has 2 or 3 entries IIRC, and > is already greatly expanded in Greg KH's git tree - so this will make > it into 2.6.23. This blacklist alone is obviously not going to cut it; > we've got rid of the scanner kernel module because it was painful to > keep it up to date and to update it on user's machine every time we > needed to add a USB ID. This blacklist is just the same thing. > > - a sysfs attribute has been added to USB devices that allows turning > off the USB autosuspend feature on a per-device basis. This attribute > can be found under /sys/bus/usb/devices/*/power/level. > > > By doing echo on > /sys/bus/usb/devices/<device id>/power/level, it is > possible to disable the USB autosuspend feature (and wake the scanner > up if it's suspended). > > By doing echo suspend > /sys/bus/usb/devices/<device id>/power/level, > it is possible to force a device into suspend mode (and it won't be > waken up automatically). > > By doing echo auto > /sys/bus/usb/devices/<device id>/power/level, the > default behaviour of automatically suspending the device can be > restored. > > > So, as of a few minutes ago, the udev rules generated by sane-desc > include a new RUN rule that will disable the USB autosuspend feature > for all the scanners we know. > > > That's the end of "black scans" as long as you run a kernel >= 2.6.22 > and this sysfs interface doesn't change :-) > > Have fun, > > JB. -- Clay Weber http://kubuntuforums.net http://claydoh.com http://emacdogsports.com -- some usb_devices fault if usb_suspend enabled https://bugs.launchpad.net/bugs/85488 You received this bug notification because you are a member of Ubuntu Bugs, which is the bug contact for Ubuntu. -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs