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<base href="https://bugs.freedesktop.org/" />
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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - Graphics problems with intel_iommu=on on Linux >= 3.7"
href="https://bugs.freedesktop.org/show_bug.cgi?id=91127">91127</a>
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<tr>
<th>Summary</th>
<td>Graphics problems with intel_iommu=on on Linux >= 3.7
</td>
</tr>
<tr>
<th>Product</th>
<td>DRI
</td>
</tr>
<tr>
<th>Version</th>
<td>unspecified
</td>
</tr>
<tr>
<th>Hardware</th>
<td>x86-64 (AMD64)
</td>
</tr>
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<th>OS</th>
<td>Linux (All)
</td>
</tr>
<tr>
<th>Status</th>
<td>NEW
</td>
</tr>
<tr>
<th>Severity</th>
<td>normal
</td>
</tr>
<tr>
<th>Priority</th>
<td>medium
</td>
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<th>Component</th>
<td>DRM/Intel
</td>
</tr>
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<th>Assignee</th>
<td>intel-gfx-bugs@lists.freedesktop.org
</td>
</tr>
<tr>
<th>Reporter</th>
<td>lantw44@gmail.com
</td>
</tr>
<tr>
<th>QA Contact</th>
<td>intel-gfx-bugs@lists.freedesktop.org
</td>
</tr>
<tr>
<th>CC</th>
<td>intel-gfx-bugs@lists.freedesktop.org
</td>
</tr></table>
<p>
<div>
<pre>Created <span class=""><a href="attachment.cgi?id=116752" name="attach_116752" title="Serial console log of Linux 4.1">attachment 116752</a> <a href="attachment.cgi?id=116752&action=edit" title="Serial console log of Linux 4.1">[details]</a></span>
Serial console log of Linux 4.1
I found Intel-IOMMU.txt in Linux documentation says I should file a bug if
intel_iommu=igfx_off fixes anything.
When using Linux 3.7 or later versions, characters on the screen become broken
after the graphics driver is loaded. Here is the screenshot. It is the same as
<a class="bz_bug_link
bz_status_REOPENED "
title="REOPENED - After upgrading to Linux 3.19, desktop no longer works in Xen 4.5.0 dom0"
href="show_bug.cgi?id=90037">bug 90037</a>, so I don't attach the screenshot again:
<a href="https://bugs.freedesktop.org/attachment.cgi?id=115079">https://bugs.freedesktop.org/attachment.cgi?id=115079</a>
After the display server (Xorg or Wayland) is started, it shows more errors and
crashes the system, so I cannot access the system to run dmesg or other
commands. I will attach a serial console log instead.
git bisect says the bad commit is
<a href="https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=398b7a1">https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=398b7a1</a>
If I use intel_iommu=igfx_off, there is no graphics problem.
I found some behavior differences between Linux 3.6 and Linux 3.7.
<a class="bz_bug_link
bz_status_REOPENED "
title="REOPENED - After upgrading to Linux 3.19, desktop no longer works in Xen 4.5.0 dom0"
href="show_bug.cgi?id=90037#c8">https://bugs.freedesktop.org/show_bug.cgi?id=90037#c8</a>
(CPU and GPU)
Intel Core i5 CPU 650 @ 3.20GHz
Intel Ironlake Desktop
(Motherboard)
ASUSTeK Computer INC. P7H55D-M EVO</pre>
</div>
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