linux-kernel - Re: Lenovo 3000 N100 i8042 problems

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Message-ID: <alpine.LNX.1.00.0809041957430.19665@iabervon.org>
Date:	Thu, 4 Sep 2008 20:05:20 -0400 (EDT)
From:	Daniel Barkalow <barkalow@...ervon.org>
To:	Dmitry Torokhov <dmitry.torokhov@...il.com>
cc:	Jiri Kosina <jkosina@...e.cz>, linux-kernel@...r.kernel.org,
	Christopher Desjardins <cddesjardins@...il.com>
Subject: Re: Lenovo 3000 N100 i8042 problems

On Wed, 3 Sep 2008, Daniel Barkalow wrote:

> On Wed, 3 Sep 2008, Dmitry Torokhov wrote:
> 
> > On Tue, Sep 02, 2008 at 12:16:15PM -0400, Daniel Barkalow wrote:
> > > legacy mode only has a bug that doesn't matter to Windows, and active mux 
> > > may have some of the usual problems but nothing I particularly noticed.
> > > 
> > > I noticed that, when my i8042 would stop working, it would generally have 
> > > just delivered one mouse interrupt to CPU1 after never previously doing 
> > > so. Perhaps there's some sort of deadlock in the Linux i8042 driver when 
> > > both cores are unexpectedly getting interrupts from the two devices at 
> > > once? I could understand there being a Linux bug only triggered by quirky 
> > > hardware that only applies to legacy mode, which was just uncovered by 
> > > this patch.
> > >
> > 
> > I am not sure, internally we the kernel still deals with 2 interrupt
> > sources (KBD and AUX) regardless whether it is in legacy or active
> > multiplexing mode...
> > 
> > Does it take long to trigger the bug? You coudl try doing "echo 1 >
> > /sys/modules/i8042/parameters/debug" and thend me dmesg or
> > /var/log/messages after the bug was triggered - I might see something
> > there. But please be aware that if you send me such a log I can decode
> > everything that you have been typing...
> 
> It's usually within an hour of the right usage pattern. I'll try to 
> trigger it with debugging on while not typing anything secret Thursday 
> evening.

Attached. This has me typing some unimportant stuff, and then it sticks, 
then I plug in a USB keyboard, then I tried unbinding the i8042 and 
binding it again; the audio stuttered briefly, and recovered, and I did it 
again, and then saved this log.

	-Daniel
*This .sig left intentionally blank*
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