[Openchrome-devel] K8M800 artifacts, trac #145, trac #164

[Benno Schulenberg]

Hello Thomas,

In trac tickets #145 and #164 two people seemingly independently
found kernel commit a0a6dd0b221260be1e3da725e6b49797e5fa7429
(DRM commit 6c04185857694b2293046b7ea1d4515404a740c3) to be the 
cause for screen corruptions they see on K8M800 and VN800 chips.

  http://www.openchrome.org/trac/ticket/145
  http://www.openchrome.org/trac/ticket/164

Andrey Melentyev wrote:
> Here's the commitdiff:
>http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commitdiff;h=a0a6dd0b221260be1e3da725e6b49797e5fa7429

(So, Xavier, it appears you were right in your suspicion that it was 
a kernel change that causes this.  :)

Is there anything in the diff that leaps at you, Thomas?  Or should 
the reporters file a bug against DRM so you can look at it later?

The following two statements seem strange to me:

   (void) *paused_at;

   ptr = ((volatile char *)paused_at - dev_priv->dma_ptr) + ...

What are they supposed to do?

Benno