On 25.10.2018 06:37, Hao Wei Tee wrote:
Hi, There are multiple reports[1][2][3] (more elsewhere on the internet) of USB 3 GbE adapters throwing EPROTO errors on USB transfer especially when the devices are under load. Both of the two common chipsets (Realtek RTL8153 (r8152[4]) and Asix AX88179 (ax88179_178a[5])) seem to exhibit this behaviour. [1]: https://bugzilla.kernel.org/show_bug.cgi?id=75381 [2]: https://bugzilla.kernel.org/show_bug.cgi?id=196747 [3]: https://bugzilla.kernel.org/show_bug.cgi?id=198931 [4]: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/drivers/net/usb/r8152.c [5]: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/drivers/net/usb/ax88179_178a.c I'm trying to figure out why this happens (while it doesn't seem to happen on other OSes, but I'm not sure). I think it's unlikely that both drivers are buggy, so perhaps it is something to do with the USB stack instead of the device drivers. It wouldn't be surprising if both devices actually don't adhere to the USB specs properly and other OSes are just more tolerant of that (?) but that is just conjecture on my part. Does anyone have any ideas?
Reproducing the issue with a recent kernel with xhci traces enabled should show the reason for EPROTO error. Add xhci traces before triggering the issue with: mount -t debugfs none /sys/kernel/debug echo 81920 > /sys/kernel/debug/tracing/buffer_size_kb echo 1 > /sys/kernel/debug/tracing/events/xhci-hcd/enable after issue is triggered save and send the trace at /sys/kernel/debug/tracing/trace Note that it might be huge -Mathias
