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<b><a class="bz_bug_link
bz_status_NEW "
title="NEW - [bdw-u iommu] DMAR error -> GPU hang"
href="https://bugs.freedesktop.org/show_bug.cgi?id=89360#c20">Comment # 20</a>
on <a class="bz_bug_link
bz_status_NEW "
title="NEW - [bdw-u iommu] DMAR error -> GPU hang"
href="https://bugs.freedesktop.org/show_bug.cgi?id=89360">bug 89360</a>
from <span class="vcard"><a class="email" href="mailto:dwmw2@infradead.org" title="David Woodhouse <dwmw2@infradead.org>"> <span class="fn">David Woodhouse</span></a>
</span></b>
<pre>Looking at the first two dumps, this looks like it might be a simple driver
bug. The driver forgets to use the DMA API and wrongly just hands a physical
address to the device. The device does DMA to that invalid address, takes a
well-deserved fault, and is subsequently unhappy.
The faulting addresses do not look like addresses which would be given out as
virtual DMA addresses by the DMA API. Such addresses would typically start at
0xfffff000 and grow downwards.</pre>
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