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<base href="https://bugs.freedesktop.org/" />
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<body><table border="1" cellspacing="0" cellpadding="8">
<tr>
<th>Priority</th>
<td>medium
</td>
</tr>
<tr>
<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW --- - [HSW ULT] eDP backlight regression at 1920x1080"
href="https://bugs.freedesktop.org/show_bug.cgi?id=68355">68355</a>
</td>
</tr>
<tr>
<th>Assignee</th>
<td>intel-gfx-bugs@lists.freedesktop.org
</td>
</tr>
<tr>
<th>Summary</th>
<td>[HSW ULT] eDP backlight regression at 1920x1080
</td>
</tr>
<tr>
<th>QA Contact</th>
<td>intel-gfx-bugs@lists.freedesktop.org
</td>
</tr>
<tr>
<th>Severity</th>
<td>normal
</td>
</tr>
<tr>
<th>Classification</th>
<td>Unclassified
</td>
</tr>
<tr>
<th>OS</th>
<td>All
</td>
</tr>
<tr>
<th>Reporter</th>
<td>enabfluw@gmail.com
</td>
</tr>
<tr>
<th>Hardware</th>
<td>Other
</td>
</tr>
<tr>
<th>Status</th>
<td>NEW
</td>
</tr>
<tr>
<th>Version</th>
<td>XOrg CVS
</td>
</tr>
<tr>
<th>Component</th>
<td>DRM/Intel
</td>
</tr>
<tr>
<th>Product</th>
<td>DRI
</td>
</tr></table>
<p>
<div>
<pre>Created <span class=""><a href="attachment.cgi?id=84358" name="attach_84358" title="dmesg for failing rc1 kernel with drm.debug=6">attachment 84358</a> <a href="attachment.cgi?id=84358&action=edit" title="dmesg for failing rc1 kernel with drm.debug=6">[details]</a></span>
dmesg for failing rc1 kernel with drm.debug=6
System environment:
-- chipset: HSW ULT
-- system architecture: 64-bit
-- xf86-video-intel:
-- xserver:
-- mesa:
-- libdrm:
-- kernel: 3.11.0-031100rc2-generic
-- Linux distribution: Linux Mint 15 Olivia
-- Machine or mobo model: Acer Aspire S3-392-9460
-- Display connector: eDP1
Reproducing steps:
1. Install 3.11.0-rc1, reboot, watch it work
2. Install 3.11.0-rc2, reboot, watch it fail
3. Install 3.11.0-996.201308070456, reboot, watch it work
4. Install 3.11.0-996.201308080456 (notice the date is just the next day),
reboot, watch it fail
5. Install any kernel after rc1 or the 996.20130807, reboot, watch it fail.
Additional info:
GRUB_CMDLINE_LINUX="drm.debug=6 acpi_backlight=vendor"
I can get native 1920x1080 resolution to work on a "failing" kernel by doing
the following:
1. Boot any "failing" kernel
2. Watch everything go black
3. Blindly log into X and open a terminal
4. xrandr -s 800x600 (or some other lower resolution than 1920x1080)
5. Watch the screen flash for a millisecond and then remain black
6. Ctrl+Alt+F7 to a tty, see it switch to 1920x1080
7. Ctrl+Alt+F8 to get back to X, see it switch to the xrandr'd resolution
8. xrandr -s 1920x1080 and watch it work correctly!
More logs to come...</pre>
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