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<b><a class="bz_bug_link
bz_status_NEW "
title="NEW --- - drm:i915_hangcheck_elapsed on 3.11.6-4-desktop"
href="https://bugs.freedesktop.org/show_bug.cgi?id=73261#c13">Comment # 13</a>
on <a class="bz_bug_link
bz_status_NEW "
title="NEW --- - drm:i915_hangcheck_elapsed on 3.11.6-4-desktop"
href="https://bugs.freedesktop.org/show_bug.cgi?id=73261">bug 73261</a>
from <span class="vcard"><a class="email" href="mailto:chris@chris-wilson.co.uk" title="Chris Wilson <chris@chris-wilson.co.uk>"> <span class="fn">Chris Wilson</span></a>
</span></b>
<pre>Interesting. It looks like there was a CPU access that overwrote the first few
megabytes of video RAM after i915.ko was loaded but before X started. The hang
occurs because we write some instructions into the ring early which are
overwritten before we execute the first batch (the actual instructions for the
batches are fine). Since we do not appear to overwrite any batches, that leads
me to the conclusion that it is not the GPU (following invalid userspace
commands) doing the overwriting, but access by the CPU. Ergo this is a nasty
BIOS bug, and most likely prevented by a working fastboot or bios update.</pre>
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