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        <tr>
          <th>Priority</th>
          <td>medium
          </td>
        </tr>

        <tr>
          <th>Bug ID</th>
          <td><a class="bz_bug_link 
          bz_status_NEW "
   title="NEW --- - [Acer Aspire V5-573G] Black screen on boot due to low brightness setting"
   href="https://bugs.freedesktop.org/show_bug.cgi?id=71596">71596</a>
          </td>
        </tr>

        <tr>
          <th>CC</th>
          <td>intel-gfx-bugs@lists.freedesktop.org
          </td>
        </tr>

        <tr>
          <th>Assignee</th>
          <td>intel-gfx-bugs@lists.freedesktop.org
          </td>
        </tr>

        <tr>
          <th>Summary</th>
          <td>[Acer Aspire V5-573G] Black screen on boot due to low brightness setting
          </td>
        </tr>

        <tr>
          <th>QA Contact</th>
          <td>intel-gfx-bugs@lists.freedesktop.org
          </td>
        </tr>

        <tr>
          <th>Severity</th>
          <td>minor
          </td>
        </tr>

        <tr>
          <th>Classification</th>
          <td>Unclassified
          </td>
        </tr>

        <tr>
          <th>OS</th>
          <td>Linux (All)
          </td>
        </tr>

        <tr>
          <th>Reporter</th>
          <td>mario.kleinsasser@gmail.com
          </td>
        </tr>

        <tr>
          <th>Hardware</th>
          <td>x86-64 (AMD64)
          </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=89178" name="attach_89178" title="Hardware information">attachment 89178</a> <a href="attachment.cgi?id=89178&action=edit" title="Hardware information">[details]</a></span>
Hardware information

In the last three weeks I've narrowed down the bug described in the
subject through Ubuntu launchpad. My new Laptop (Acer Aspire V5-573G)
with new Haswell CPU shows a black screen on reboot because the
brightness is on zero level. I verified this behaviour with the latest
mainline kernel from
<a href="http://kernel.ubuntu.com/~kernel-ppa/mainline/v3.12-trusty/">http://kernel.ubuntu.com/~kernel-ppa/mainline/v3.12-trusty/</a>

I have done the bisect process and tracked the bug down to the following
commit.

For explanation:
good commit means: The laptop starts with display brightness on full
power, but low(er) resolution and the Fn+ keys are not working
bad commit means: The laptop starts with black display (0 brightness),
Fn+ keys are working and you can level up the brightness trough the
Fn+ keys. The resolution is the native LCD hardware display resolution

Bisect output:

70b12bb415463c1bd146b67c5fbf6784fd046ad9 is the first bad commit
commit 70b12bb415463c1bd146b67c5fbf6784fd046ad9
Author: Paulo Zanoni <<a href="mailto:paulo.r.zanoni@intel.com">paulo.r.zanoni@intel.com</a>>
Date: Tue Nov 20 13:32:30 2012 -0200

    drm/i915: promote Haswell to full support

    Since it should be working a little bit better now.

    Signed-off-by: Paulo Zanoni <<a href="mailto:paulo.r.zanoni@intel.com">paulo.r.zanoni@intel.com</a>>
    Signed-off-by: Daniel Vetter <<a href="mailto:daniel.vetter@ffwll.ch">daniel.vetter@ffwll.ch</a>>

:040000 040000 f93a7761de2157a8be61f20ca9a5499264bb5c55
1fed098470278830f06b0bca1706f61ba231d38d M drivers

For the full bug report and the additional hardware information please
see <a href="https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1239183">https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1239183</a>

I've also searched the LKML and maybe this bug could be in conjunction
with <a href="http://marc.info/?t=137837786100005&r=1&w=2">http://marc.info/?t=137837786100005&r=1&w=2</a></pre>
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