Re: [BUG] r200 dri driver deadlocks

Felix Kühling
2004-09-06T10:48:57Z

On Sun, 05 Sep 2004 20:14:43 -0400
Lee Revell <rlrevell@joe-job.com> wrote:

> On Sun, 2004-09-05 at 16:18, Patrick McFarland wrote:
[snip]
> >
> > That shouldn't matter, should it? The userland stuff should never lock
> > the machine up.
> > I'll test it anyhow, though.
>
> No, it shouldn't. Anything that directly accesses hardware belongs in
> the kernel. How to fix this is a pretty hot topic now.

That's not the whole truth. There are just too many ways to lock up
those 3D chips. For instance I fixed a lockup in the r100 driver where
the order in which state changing commands were sent to the hardware
would cause a lockup. Each individual state changing command is
perfectly valid. Finding all permutations that trigger a lockup would
have been too much of a hassle and may not even have been true for all
supported hardware out there. So we made the user-space driver emit
state changing commands in a fixed order, which seems to work
everywhere.

Regars,
Felix

>
> Lee
>

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