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    <body><table border="1" cellspacing="0" cellpadding="8">
        <tr>
          <th>Bug ID</th>
          <td><a class="bz_bug_link 
          bz_status_NEW "
   title="NEW - GeForce GT 750M Mac Edition backlight"
   href="https://bugs.freedesktop.org/show_bug.cgi?id=110973">110973</a>
          </td>
        </tr>

        <tr>
          <th>Summary</th>
          <td>GeForce GT 750M Mac Edition backlight
          </td>
        </tr>

        <tr>
          <th>Product</th>
          <td>Mesa
          </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>

        <tr>
          <th>Component</th>
          <td>Drivers/DRI/nouveau
          </td>
        </tr>

        <tr>
          <th>Assignee</th>
          <td>nouveau@lists.freedesktop.org
          </td>
        </tr>

        <tr>
          <th>Reporter</th>
          <td>ak@axet.ru
          </td>
        </tr>

        <tr>
          <th>QA Contact</th>
          <td>nouveau@lists.freedesktop.org
          </td>
        </tr></table>
      <p>
        <div>
        <pre>Created <span class=""><a href="attachment.cgi?id=144616" name="attach_144616" title="sudo acpidump -o acpidump.txt">attachment 144616</a> <a href="attachment.cgi?id=144616&action=edit" title="sudo acpidump -o acpidump.txt">[details]</a></span>
sudo acpidump -o acpidump.txt

Hello!

I notice when laptop display went off, it keep backlight on.

Technically speaking this:

# xset dpms force off

only set screen to black, without turning off LCD backlight.

My kernel has "acpi_backlight=vendor" which enables backlight control from
function keys and gnome recognize those actions by displaying popup with
current brightness level.

Everything seems works fine, I've been able to turn display off using:

# echo 0 > /sys/devices/pnp0/00:03/backlight/gmux_backlight/brightness

But still no luck with 'xset'.

axet@axet-laptop:~$ ls -al /sys/class/backlight/
total 0
drwxr-xr-x  2 root root 0 июн 23 23:13 .
drwxr-xr-x 67 root root 0 июн 23 23:13 ..
lrwxrwxrwx  1 root root 0 июн 23 23:13 gmux_backlight ->
../../devices/pnp0/00:03/backlight/gmux_backlight
axet@axet-laptop:~$



Maybe related: <a class="bz_bug_link 
          bz_status_NEW "
   title="NEW - Backlight does not work on a MacBookAir3,2"
   href="show_bug.cgi?id=106869">https://bugs.freedesktop.org/show_bug.cgi?id=106869</a></pre>
        </div>
      </p>


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