> On Jun 6, 2019, at 10:03 AM, Alan Stern <stern@xxxxxxxxxxxxxxxxxxx> wrote: > > EPERM means that the file descriptor was not opened with write access. > It has nothing to do with reset failures. Yes, I was confused by that as well so spent some time instrumenting the kernel. It definitely is open for writing, and get’s by the initial f_mode check in devio.c:usbdev_do_ioctl. Is it possibly a default error that’s returned when some deeper error is encountered? Unfortunately I was unable to determine exactly where it was coming from... Seth
