[quoted lines by Alan Stern on 2015/02/11 at 11:13 -0500] >Hmmm. In addition to usbmon, you can try writing 1 to >/sys/module/usbcore/parameters/usbfs_snoop and then seeing what shows >up in the dmesg log. Looking at the snoop logs is hinting that I may need to add another piece to this puzzle. It's showing that the urb doesn't complete until the device is finally closed. This makes sense because, being turned off, the device isn't responding to the probes. That's also what I used to see when using an actual signal handler. What I didn't mention (because I didn't think it'd be significant) is that I've started seeing the current problem when I switched to using signalfd so that a signal handler wouldn't be necessary. What I see when using signalfd is that the signal arrives (the signalfd file descriptor becomes readable) almost immediately, i.e. as soon as the poll() is entered to wait for a response from the first probe. Reading the struct signalfd_siginfo from the signalfd file descriptor does give the expected signal number. So now, perhaps the question is could it be that signalfd data is arriving too early? Could signalfd and signal handler behaviour really be different like that? -- Dave Mielke | 2213 Fox Crescent | The Bible is the very Word of God. Phone: 1-613-726-0014 | Ottawa, Ontario | http://Mielke.cc/bible/ EMail: dave@xxxxxxxxx | Canada K2A 1H7 | http://FamilyRadio.com/ -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
