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<b><a class="bz_bug_link
bz_status_NEW "
title="NEW - [SNB] igt@drv_module_reload@basic-reload-final fails and hard hangs the system"
href="https://bugs.freedesktop.org/show_bug.cgi?id=100858#c2">Comment # 2</a>
on <a class="bz_bug_link
bz_status_NEW "
title="NEW - [SNB] igt@drv_module_reload@basic-reload-final fails and hard hangs the system"
href="https://bugs.freedesktop.org/show_bug.cgi?id=100858">bug 100858</a>
from <span class="vcard"><a class="email" href="mailto:krisman@collabora.co.uk" title="krisman@collabora.co.uk">krisman@collabora.co.uk</a>
</span></b>
<pre>(In reply to Chris Wilson from <a href="show_bug.cgi?id=100858#c1">comment #1</a>)
<span class="quote">> The answer lies in if the GPU didn't write the dword to where we wanted,
> where did it write it? And the same worrying question will be for lots of
> different ops. The HWS is intact otherwise it would have complained about a
> gpu hang... Actually no, that test isn't checking so that's a more
> reasonable explanation that the HWS write also went astray, i.e. it is
> likely that nothing is right in the way the GPU is addressing memory.
>
> In load/unload we do a GPU reset, so everything should be sane...
>
> Remove the store dword check and see it it still hard hangs. If so, we can
> start removing chunks from the load/unload sequence and see at what point it
> works.</span >
It doesn't hard hang without the store_dword sequence. The hang happens on
gem_write when executing the blt engine. One interesting aspect is that the
issue is only reproducible with intel_iommu=on. If that parameter is disabled,
the test succeeds and the system never hangs.</pre>
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