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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 - [BSW Bisected]Display show black screen when starting gnome-session"
href="https://bugs.freedesktop.org/show_bug.cgi?id=88081">88081</a>
</td>
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<tr>
<th>Summary</th>
<td>[BSW Bisected]Display show black screen when starting gnome-session
</td>
</tr>
<tr>
<th>Product</th>
<td>DRI
</td>
</tr>
<tr>
<th>Version</th>
<td>unspecified
</td>
</tr>
<tr>
<th>Hardware</th>
<td>Other
</td>
</tr>
<tr>
<th>OS</th>
<td>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>
</tr>
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<th>Component</th>
<td>DRM/Intel
</td>
</tr>
<tr>
<th>Assignee</th>
<td>intel-gfx-bugs@lists.freedesktop.org
</td>
</tr>
<tr>
<th>Reporter</th>
<td>wendy.wang@intel.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=111803" name="attach_111803" title="dmesg-gnome-blank">attachment 111803</a> <a href="attachment.cgi?id=111803&action=edit" title="dmesg-gnome-blank">[details]</a></span>
dmesg-gnome-blank
System Environment:
--------------------------
Platform: BSW
OS Distribution: Ubuntu 14.04
Kernel regression:
both latest drm-intel-nightly (07d0c831d9207c937595f081c8fddbddbf53756f)
and drm-intel-next-queued branch fail
Kernel Regression:
--------------------------
Yes, bisected on drm-intel-next-queued branch:
371abae844ede392066bfc21202b2e40f4a654d1 is the first bad commit
commit 371abae844ede392066bfc21202b2e40f4a654d1
Author: Deepak M <<a href="mailto:m.deepak@intel.com">m.deepak@intel.com</a>>
Date: Mon Dec 15 15:58:21 2014 +0530
Commit: Daniel Vetter <<a href="mailto:daniel.vetter@ffwll.ch">daniel.vetter@ffwll.ch</a>>
CommitDate: Mon Dec 15 11:25:29 2014 +0100
drm/i915: Parsing LFP brightness control from VBT
LFP brighness control from the VBT block 43 indicates which
controller is used for brightness.
LFP1 brightness control method:
Bit 7-4 = This field controller number of the brightnes controller.
0 = Controller 0
1 = Controller 1
2 = Controller 2
3 = Controller 3
Others = Reserved
Bits 3-0 = This field specifies the brightness control pin to be used on
the
platform.
0 = PMIC pin is used for brightness control
1 = LPSS PWM is used for brightness control
2 = Display DDI is used for brightness control
3 = CABC method to control brightness
Others = Reserved
Adding the above fields in dev_priv->vbt and corresponding changes in
parse_backlight()
v2: Jani's review comments addressed
- Move PWM definitions to intel_bios.h
- Moving vbt_version to intel_vbt_data
- Rename brightness to bl_ctrl_data
- Logging just control_pin instead of string
- Avoid adding vbt_version in dev_priv
- Since only DDI option is available as of now, let control pin DDI
affect dev_priv->vbt.backlight.present
v3: Jani's review comments addressed
- Drop control_pin
- Use bdb->version
- set controller to 0 instead of using control pin define
- check controller bounds
- remove superfluous changes in intel_parse_bios
Signed-off-by: Deepak M <<a href="mailto:m.deepak@intel.com">m.deepak@intel.com</a>>
Signed-off-by: Vandana Kannan <<a href="mailto:vandana.kannan@intel.com">vandana.kannan@intel.com</a>>
Reviewed-by: Jani Nikula <<a href="mailto:jani.nikula@intel.com">jani.nikula@intel.com</a>>
Signed-off-by: Daniel Vetter <<a href="mailto:daniel.vetter@ffwll.ch">daniel.vetter@ffwll.ch</a>>
:040000 040000 1a70f7733307b3dc8545fae58760d314f59f1087
75ec00642c7ee92fda81d0a2f0d74971f8a90164 M drivers
Reproduce steps:
1. boot into system
2. xinit &
3. screen
4. gnome-session &
will observe display show black screen when starting gnome-session.</pre>
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