(In reply to Alex Deucher from comment #1)
> please attach your xorg log and dmesg output.  In most cases this can be
> ignored if things are working properly.

Hi Alex. I'll be attaching them later today. Sorry, that was my intention but I
got distracted by another bug in Xserver (it was the bug in X that allowed me
to discover this error in dmesg). However, there was nothing interesting in
both files from what I remember.

I'm pretty sure it was not appearing in a previous combination of mesa, ddx,
drm and kernel. I could try with a previous combination. I'll begin with an
older kernel.

If this error can be ignored when things are working properly, we probably
shouldn't output an error. It should be at most a warning and be displayed as
an error only if it fails seriously, don't you think?