2009/8/9 M. Warner Losh <[email protected]>: > In message: <[email protected]> > Hans Petter Selasky <[email protected]> writes: > : On Sunday 09 August 2009 18:23:41 M. Warner Losh wrote: > : > Any ideas how to track this down? > : > : Hi, > : > : USB is only draining from "usbd_transfer_drain()" in > : /sys/dev/usb/usb_transfer.c . You could add a print including the backtrace > : and see if that function gets called when it freezes. > > Ummm. No. Adding a traceback print to a function that's called 60 > times a second in steady state doesn't seem like a viable option. > > : Else I would try to compile a fresh kernel from USB P4. There are > : some patches there in relation to the recent newbus lock change, > : that might help. > > This kernel predates the newbus lock change. > > : USB uses uppercase "WDRAIN". Is your printout lowercase "wdrain" ? > > Yes.
That's used by the buffer cache in order to reduce pressure of asynchronous writes. It waits for other writes to complete before to go on. Probabilly, I/O requests get stuck for another reasong starving the asynchronous requests queue flushing. Attilio -- Peace can only be achieved by understanding - A. Einstein _______________________________________________ [email protected] mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-usb To unsubscribe, send any mail to "[email protected]"
