On Wednesday 21 December 2011 12:29:49 Andriy Gapon wrote: > on 20/12/2011 14:25 Andriy Gapon said the following: > > I just wanted to draw your attention to the fact that obtaining any locks > > in the kdb context (or USB polling code in general, even) is not a good > > idea. Chances of getting into trouble on those locks are probably quite > > moderate or even low, but they do exist. I am not sure if you are > > getting any bug reports about such troubles :-) Regular users probably > > do not use kdb too often and a panic for them is just a "crash", so they > > likely do not expect anything usable/debuggable after that :-) > > Looking some more at the code I just got myself confused as to how the > dumping to a umass device could work when the scheduler is stopped. > It seems that the umass_command_start -> usbd_transfer_start -> > usbd_callback_ss_done_defer functions would always put a transfer request > onto a queue and try to wake up a thread to process that queue and the > request. But that's obviously not going to work when the other thread is > not going to be run. Have I missed a code path that leads directly to the > controller in this context? Thank you for your help.
Hi, Those threads should be polled when calling usbd_transfer_poll(). I.E. the wakeup should be stubbed in the !scheduler_running case. --HPS _______________________________________________ freebsd-current@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-current To unsubscribe, send any mail to "freebsd-current-unsubscr...@freebsd.org"
