Subject: Re: old radeon latency problem still unfixed?
From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
To: Lee Revell <rlrevell@joe-job.com>
Cc: Arjan van de Ven <arjan@infradead.org>,
       linux-kernel <linux-kernel@vger.kernel.org>
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Date: Mon, 27 Feb 2006 08:11:33 +1100
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> AFAICT it's more like trading 3D performance for having audio work at
> all.  Other video drivers that were too aggressive and caused audio
> dropouts (VIA) were fixed, even though there was a slight performance
> cost.

In addition, the radeon DRI shouldn't do active spinning like that in
"normal" circumstances ... it should instead block on interrupts. if it
does, I suppose that could safely be considered as a bug in the radeon
DRM/DRI driver. It will do such loops on engine reset and such, which
happen on X launch, VT switches or in case of lockups... I have to
double check what happens in the code path used for 2d/3d transitions
though, those might be a problem.

Ben.


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