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
