On Mon, 21 Feb 2005, Glenn Maynard wrote: > > It's known that some USB mass storage devices are unable to handle control > > requests on endpoint 0 while carrying out SCSI commands. Since reading > > the serial string involves just such a control request, it's not > > surprising that your stick runs into trouble. > > > > Your log doesn't show usb-storage hanging. In fact it doesn't show > > anything at all after the error messages from trying to read the serial. > > What happens when the hang occurs? What does Alt-SysRq-T show for the > > usb-storage process and the SCSI error-handler process? If you turn on > > usb-storage verbose debugging, what does that reveal? > > Sorry, I had only enabled USB verbose debug, not USB Mass Storage verbose > debug. Logs, with debug enabled, timestamps added and Alt-SysRq-T output > at the first timeout attached.
If I'm reading your timestamps correctly (seconds and fractions of a second), you made the stack dump only 4 seconds after things stopped happening. That's not long enough; the SCSI drivers have a timeout of 10 seconds (I think) for reads and 30 seconds for error recovery, which proceeds in several stages with lots of retries. You should wait a few minutes for things to settle down before assuming that the system has hung. Alan Stern ------------------------------------------------------- SF email is sponsored by - The IT Product Guide Read honest & candid reviews on hundreds of IT Products from real users. Discover which products truly live up to the hype. Start reading now. http://ads.osdn.com/?ad_id=6595&alloc_id=14396&op=click _______________________________________________ [email protected] To unsubscribe, use the last form field at: https://lists.sourceforge.net/lists/listinfo/linux-usb-devel
