Re: [PATCH] make ps2 mouse work ...

From: Vojtech Pavlik
Date: Wed Jun 16 2004 - 07:13:43 EST


On Tue, Jun 15, 2004 at 08:56:11PM -0700, Andrew Morton wrote:

> > I found this problem on a MIPS machine. The problem is
> > likely to happen on other register-rich RISC arches too.
> >
> > cmdcnt needs to be volatile since it is modified by
> > irq routine and read by normal process context.
>
> volatile is not the preferred way to fix this up. This points at either a
> locking error in the psmouse driver or a missing "memory" thingy in the
> mips port somewhere.
>
> Please describe the bug which led to this patch. Where was it getting stuck?

My current BK tree has this fixed using atomic bitfields, which do
compilation and memory barriers. I plan to sync it to Linus post 2.6.7.

--
Vojtech Pavlik
SuSE Labs, SuSE CR
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