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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - [i915] intel_backlight does not function - Lenovo X1 Yoga OLED"
href="https://bugs.freedesktop.org/show_bug.cgi?id=97883">97883</a>
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<th>Summary</th>
<td>[i915] intel_backlight does not function - Lenovo X1 Yoga OLED
</td>
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<th>Product</th>
<td>DRI
</td>
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<th>Version</th>
<td>DRI git
</td>
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<th>Hardware</th>
<td>Other
</td>
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<th>OS</th>
<td>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
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<th>Assignee</th>
<td>intel-gfx-bugs@lists.freedesktop.org
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<th>Reporter</th>
<td>dan@ified.ca
</td>
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<th>QA Contact</th>
<td>intel-gfx-bugs@lists.freedesktop.org
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<th>CC</th>
<td>intel-gfx-bugs@lists.freedesktop.org
</td>
</tr></table>
<p>
<div>
<pre>Created <span class=""><a href="attachment.cgi?id=126688" name="attach_126688" title="Full dmesg output with drm.debug=0x1e log_buf_len=1M">attachment 126688</a> <a href="attachment.cgi?id=126688&action=edit" title="Full dmesg output with drm.debug=0x1e log_buf_len=1M">[details]</a></span>
Full dmesg output with drm.debug=0x1e log_buf_len=1M
On the OLED version of the Lenovo X1 Yoga, the intel_backlight device reports a
range of 0 to 852, but its setting has no effect. (Perhaps not too surprising
since this device technically has no backlight.) The display brightness is
always (near?) maximum when Linux is booted.
The thinkpad_acpi module does no better at providing brightness controls.
The xrandr --brightness setting is a nearly-adequate workaround, but is
occasionally reset while using X.org normally (I have not investigated the
cause yet).
Attached logs are from an Ubuntu kernel-ppa image, stamped:
cod/tip/drm-intel-next/2016-09-20 (6e05f3d3b9298a56d6f1acb474a75cf14a17c31e)
The laptop display is attached to eDP1. There is a second display attached to
DP1; I can provide logs without that if requested.
I was not able to create a vbios dump. ("Input/Output error")</pre>
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