Malte Wedel <> wrote:

> Hello Misc,
> I have OpenBSD running on a Thinkpad X1 Carbon, 3rd Gen, everything is
> working great, except for the builtin 4G modem "umb0" which detaches and
> disappears from time to time and needs a reboot to become available
> again. I found this thread which seems to be exactly my issue:
> When the issue occurs, the following is written into /var/log/messages:
> May  3 14:42:09 carbon /bsd: umb0 detached
> May  3 14:42:09 carbon /bsd: ucom0 detached
> May  3 14:42:09 carbon /bsd: umodem0 detached

I suspect this detachment is caused by the driver violating the protocol,
and the device gives up.

> May  3 14:42:26 carbon /bsd: uhub0: port 4, set config 0 at addr 2 failed
> May  3 14:42:26 carbon /bsd: uhub0: device problem, disabling port 4

This is a different problem, and is believed to be a race condition on
port power-up.  This problem has been moving around for years...

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