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From:   Nathan Royce <nroycea+kernel@gmail.com>
Date:   Sun, 6 Jan 2019 13:33:09 -0600
Message-ID: <CALaQ_hpy==CbwmF25eoYM6xb7dAxQZ3y1DmFMDDv-GtK8p3NPg@mail.gmail.com>
Subject: Re: kernel: xhci_hcd 0000:00:14.0: ERROR unknown event type 37 -
 Kernel 4.19.13
To:     Mathias Nyman <mathias.nyman@linux.intel.com>
Cc:     linux-kernel@vger.kernel.org, linux-usb@vger.kernel.org,
        Alan Stern <stern@rowland.harvard.edu>,
        gregkh@linuxfoundation.org
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I'm only posting to say I'm still waiting...
The error came up while I slept, and when I copied that log and looked
at it (yes, it WAS huge, just as you said), the timestamps at the
head/tail were much later than the journal logged times.
So I made a little script to monitor the journal kernel entries for
that message and have it copy the file after maybe 5 seconds. And now,
I'm just waiting for that error to occur again.

On Wed, Jan 2, 2019 at 5:32 AM Mathias Nyman
<mathias.nyman@linux.intel.com> wrote:
>
> The event type 37 is a host controller event, most likely a event ring full error.
>
> So there are probably so many events that we fill the event ring before we can handle them.
>
> Could you take traces of this?
> Note that the trace file will be huge.
>
> 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
>
> copy the traces somewhere safe once the error is triggered:
> cp /sys/kernel/debug/tracing/trace  /<somewhere>
>
> -Mathias