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Message-ID: <Pine.LNX.4.44L0.1610211245510.1898-100000@iolanthe.rowland.org>
Date: Fri, 21 Oct 2016 12:54:09 -0400 (EDT)
From: Alan Stern <stern@...land.harvard.edu>
To: Michael Thayer <michael.thayer@...cle.com>
cc: linux-kernel@...r.kernel.org, Thomas Gleixner <tglx@...utronix.de>,
Michal Necasek <michal.necasek@...cle.com>,
"Knut St. Osmundsen" <knut.osmundsen@...cle.com>
Subject: Re: PROBLEM: OHCI watchdog timeouts inside VirtualBox, probably due
to timer wheel rework
On Fri, 21 Oct 2016, Michael Thayer wrote:
> Hello Alan (LKML on CC),
>
> Contacting you about this on Thomas Gleixner's (also on CC) suggestion.
> The short summary is that when Linux 4.8.0 (also tested with a few later
> kernels) is run on a VirtualBox virtual machine with USB enabled, OHCI
> fails with the log messages "frame counter not updated; disabled" and
> "HC died; cleaning up". This seems to be due to the 250 ms interval
> watchdog running with far too short intervals, which we think is a
> consequence of the timer wheel code rework. I will refer you to a bug
> filed in Launchpad<1> for a longer description.
>
> Hope this is of interest to you.
>
> Regards,
>
> Michael
>
> <1> https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1634737
That bug description says the watchdog timer routine can be called
twice in a 4-ms period, even though it requests a 250-ms delay. Is
this really true? If it is, it sounds like a real bug in the timer
core.
Bryan Paluch reported a similar problem and said that increasing the
timeout value to 275 ms fixed it:
http://marc.info/?l=linux-usb&m=147670889009451&w=2
Does that patch also fix the "frame counter not updating" problem?
Alan Stern
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