Kernel Bug Tracker – Bug 8433
usb_suspend and scanner canoscan n670u
Last modified: 2007-09-12 11:18:57 UTC
Most recent kernel where this bug did *NOT* occur:
Distribution: ubuntu 7.04
Hardware Environment: scanner canoscan n670u
Is a usual problem with scanner and usb_suspend. The differenc is after scanner
is attached it is not working if i disable autosuspend ( echo -1 >
/sys/module/usbcore/parameters/autosuspend ) it's not working too. But if i plug
out scanner, disable autosupend, plugin and enable autosupend agene ewerything
May be there is nothing bother about and just blacklist my scanner for usb_suspend.
Created attachment 11403 [details]
here is dmesg after boot and with enabled autosuspend
Created attachment 11404 [details]
here is verbose lsusb. but if you like shor way take just this:
Bus 001 Device 008: ID 04a9:220d Canon, Inc. CanoScan N670U/N676U/LiDE 20
From the dmesg1 log, it looks like you set the autosuspend delay to 0. That's
not a good idea; it generates lots of unnecessary suspends and resumes. Try
leaving it at the default value of 2.
By the way, you should realize that
echo -1 > /sys/module/usbcore/parameters/autosuspend
doesn't really disable autosuspend. Rather, it causes autosuspend to be
disabled for new devices as they are plugged in -- but it doesn't affect the
setting for devices that are already attached. To disable autosuspend for a
particular device you should do:
echo -1 >/sys/bus/usb/devices/XXX/power/autosuspend
where XXX is the sysfs pathname of your device (in this case 1-2).
It would be interesting to see if the scanner really does need to be blacklisted
for suspend. You can test that: write -1 to the usbcore parameter, then plug in
the scanner, then set the scanner's autosuspend delay to 2 and wait for it to be
suspended. Then see if it still works.
Elmar, did you have chance to try recommendations in #3?
Well, I think we have not received sufficient information from the reporter.
We have found that many, many scanners don't like to be suspended. The current development kernel has a blacklist entry for this scanner. In the end we may blacklist the entire class.
Elmar, do you have anything new to report? Otherwise this bug report will be closed in a few days.
(In reply to comment #6)
> Elmar, do you have anything new to report? Otherwise this bug report will be
> closed in a few days.
Can you close it, please?
The scanner in question has been added to the quirks list. Closing the bug report.