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From: John Baldwin <jhb@freebsd.org>
To: freebsd-current@freebsd.org
Subject: Re: new Xorg (KMS, etc.) for Radeon 9600
Date: Mon, 23 Dec 2013 11:50:31 -0500
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 (bigwig.baldwin.cx); Mon, 23 Dec 2013 14:43:55 -0500 (EST)
Cc: dt71@gmx.com, Adrian Chadd <adrian@freebsd.org>,
 Robert Noland <rnoland@freebsd.org>, 
 =?iso-8859-1?q?Jean-S=E9bastien?= =?iso-8859-1?q?_P=E9dron?=
 <dumbbell@freebsd.org>
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On Wednesday, December 18, 2013 2:43:28 pm Adrian Chadd wrote:
> [snip]
> 
> So the standard trop of UNLOCK/WORK/RELOCK is pretty dangerous.
> There's no state re-validation going on when you re-acquire that lock.
> So, although it meets the lock requirements, it may not be 'correct'.
> 
> It's scattered throughout the code base (wifi drivers aren't an
> exception here either, sigh.)
> 
> Just something to keep in mind when you validate the 'correctness' of
> this kind of lock hack.

Agreed.  It needs fixing, but the fix needs to be correct.

-- 
John Baldwin