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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - [KBL] External display pixelated after upgrade to kernel >= 4.11.0-rc1"
href="https://bugs.freedesktop.org/show_bug.cgi?id=101639">101639</a>
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<th>Summary</th>
<td>[KBL] External display pixelated after upgrade to kernel >= 4.11.0-rc1
</td>
</tr>
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<th>Product</th>
<td>DRI
</td>
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<th>Version</th>
<td>unspecified
</td>
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<th>Hardware</th>
<td>x86-64 (AMD64)
</td>
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<th>OS</th>
<td>Linux (All)
</td>
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<th>Status</th>
<td>NEW
</td>
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<th>Severity</th>
<td>normal
</td>
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<th>Priority</th>
<td>medium
</td>
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<th>Component</th>
<td>DRM/Intel
</td>
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<th>Assignee</th>
<td>intel-gfx-bugs@lists.freedesktop.org
</td>
</tr>
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<th>Reporter</th>
<td>njkkow@gmail.com
</td>
</tr>
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<th>QA Contact</th>
<td>intel-gfx-bugs@lists.freedesktop.org
</td>
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<th>CC</th>
<td>intel-gfx-bugs@lists.freedesktop.org
</td>
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<pre>Created <span class=""><a href="attachment.cgi?id=132331" name="attach_132331" title="configs, dmesg w/ drm.debug=0xe, EDIDs, fb0 sysfs, inxi, Xorg.0.log, picture of screen">attachment 132331</a> <a href="attachment.cgi?id=132331&action=edit" title="configs, dmesg w/ drm.debug=0xe, EDIDs, fb0 sysfs, inxi, Xorg.0.log, picture of screen">[details]</a></span>
configs, dmesg w/ drm.debug=0xe, EDIDs, fb0 sysfs, inxi, Xorg.0.log, picture of
screen
I have a Thinkpad X270 with an i7 7500U / Intel HD Graphics 620, running Fedora
25, Mint, and Xubuntu (attachments are from Xubuntu.) I had been using a 26"
Vizio E261VA TV over HDMI as an external monitor for a few months without any
issues, but after upgrading to any kernel >= 4.11.0-rc1, the display becomes
very pixelated and text is almost unreadable. On 4.10 it looks fine. One
thing I noticed was that the "mode" for the fb0 device is now set to
"U:1360x768p-0". In the working kernel it's "U:1920x1080p-0". The issue only
happens over HDMI; the picture still looks fine if I use a USB-C -> VGA
adapter.
The native resolution for this TV is 1360x768, which is the resolution I run it
at, and the laptop screen is running at 1920x1080. I have tried uninstalling
the Xorg intel driver but it didn't make a difference. I have also tried
booting the kernel with the parameter video=HDMI-A-2:1920x1080M@60. That will
change the framebuffer mode back to what it was in 4.10, but I still can't seem
to get the pixelation to go away. I tried to force the EDID from VGA using
drm_kms_helper but it didn't help either. I built a kernel from
cgit.freedesktop.org/drm-tip today (6/28/17) and I still see the issue.
Attached the configs I am using for 4.10 and the drm-tip kernel.
I noticed quite a few changes in the logs for 4.11.0-rc1 involving drm/i915,
framebuffers, EDID, and HDMI, so I assume this has something to do with that.
I'm not 100% sure it involves the framebuffer, but the resolution change caught
my eye. I see the pixelation before X even starts, while the startup checks
are running down the screen.
Please let me know if I can provide any other info. Thanks!</pre>
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