Date: Fri, 21 Oct 2016 12:54:09 -0400 (EDT)
From: Alan Stern <stern@rowland.harvard.edu>
To: Michael Thayer <michael.thayer@oracle.com>
cc: linux-kernel@vger.kernel.org, Thomas Gleixner <tglx@linutronix.de>,
        Michal Necasek <michal.necasek@oracle.com>,
        "Knut St. Osmundsen" <knut.osmundsen@oracle.com>
Subject: Re: PROBLEM: OHCI watchdog timeouts inside VirtualBox, probably due
 to timer wheel rework
In-Reply-To: <e61eaf90-88c6-8e06-f3e1-6d2aceaa45c1@oracle.com>
Message-ID: <Pine.LNX.4.44L0.1610211245510.1898-100000@iolanthe.rowland.org>
MIME-Version: 1.0
Content-Type: TEXT/PLAIN; charset=US-ASCII
Sender: linux-kernel-owner@vger.kernel.org
Content-Length: 1222
Lines: 34

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