[ +CC: linux-usb ] On Wed, Oct 22, 2014 at 04:36:59PM +0100, Nix wrote: > On 22 Oct 2014, Johan Hovold outgrape: > > > On Wed, Oct 22, 2014 at 10:31:17AM +0100, Nix wrote: > >> On 14 Oct 2014, Johan Hovold verbalised: > >> > >> > On Sun, Oct 12, 2014 at 10:36:30PM +0100, Nix wrote: > >> >> I have checked: this code is being executed against a symlink that > >> >> points to /dev/ttyACM0, and the tcsetattr() succeeds. (At least, it's > >> >> succeeding on the kernel I'm running now, but of course that's 3.16.5 > >> >> with this commit reverted...) > >> > > >> > You could verify that by enabling debugging in the cdc-acm driver and > >> > making sure that the corresponding control messages are indeed sent on > >> > close. > >> > >> I have a debugging dump at > >> <http://www.esperi.org.uk/~nix/temporary/cdc-acm.log>; it's fairly > > > > What kernel were you using here? The log seems to suggest that it was > > generated with the commit in question reverted. > > Look now :) (the previous log is still there in cdc-acm-reverted.log.) Unfortunately, it seems the logs are incomplete. There are lots of entries missing (e.g. "acm_tty_install" when opening, but also some "acm_submit_read_urb"), some of which were there in your first log. Also you can disable the "acm_tty_write - count" output, which isn't really useful here. > This contains two boots -- one on which the USB key worked, and the next > (with an identical kernel) with which the key was broken. (I'm not sure > whether this problem happens at startup or shutdown time, so it seemed > best to provide both.) That's a good idea. Is it only after reboot you've seen the device fail? What if you physically disconnect and reconnect the device instead, or simply repeatedly open and close it? Johan -- 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
