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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 --- - Provide handle for ACPI to change backlight brightness, similiar to other power-related ACPI events"
   href="https://bugs.freedesktop.org/show_bug.cgi?id=66367">66367</a>
          </td>
        </tr>

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

        <tr>
          <th>Summary</th>
          <td>Provide handle for ACPI to change backlight brightness, similiar to other power-related ACPI events
          </td>
        </tr>

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

        <tr>
          <th>Severity</th>
          <td>enhancement
          </td>
        </tr>

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

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

        <tr>
          <th>Reporter</th>
          <td>peter.weber@ttyhoney.com
          </td>
        </tr>

        <tr>
          <th>Hardware</th>
          <td>All
          </td>
        </tr>

        <tr>
          <th>Status</th>
          <td>NEW
          </td>
        </tr>

        <tr>
          <th>Version</th>
          <td>unspecified
          </td>
        </tr>

        <tr>
          <th>Component</th>
          <td>general
          </td>
        </tr>

        <tr>
          <th>Product</th>
          <td>systemd
          </td>
        </tr></table>
      <p>
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        <pre>Hello!

Proposal:
Add a new handle named like "HandleBrightness" to Systemd and let it take care
of the brightness-events, which the kernel emits and signals to userspace.
Similiar to "HandleLidSwitch" or "HandleSuspendKey" and configureable via
"/etc/systemd/logind.conf". If a desktop-environment like GNOME, KDE or XFCE is
able to handle this itself, it should "inhibit" the handle.

I would avoid the postfix "Keys" because such an event could be trigged by
other things, like a light-sensor or something similiar.

Rationale:
Currently the handling of events triggered through the backlight-keys is weird
on GNU/Linux. If a key-press emits an event, the Linux-Kernel sends the event
to the userspace. At the same time, it is possible that the driver
ACPI_BACKLIGHT, inside the kernel, reacts on the event and changes the
backlight-brightness itself.

This is likely to change in future, instead the events will be only passed to
userspace.
<a href="http://lists.freedesktop.org/archives/intel-gfx/2013-March/026016.html">http://lists.freedesktop.org/archives/intel-gfx/2013-March/026016.html</a>
Patches:
<a href="https://patchwork.kernel.org/patch/2695411/">https://patchwork.kernel.org/patch/2695411/</a>
<a href="https://patchwork.kernel.org/patch/2695391/">https://patchwork.kernel.org/patch/2695391/</a>
<a href="https://patchwork.kernel.org/patch/2695401/">https://patchwork.kernel.org/patch/2695401/</a>

As a consequence the brightness-keys won't work on a terminal (TTY) or a plain
window-manager based on X11 or Wayland:
<a href="https://bugzilla.kernel.org/show_bug.cgi?id=51231#c107">https://bugzilla.kernel.org/show_bug.cgi?id=51231#c107</a>

Benefit:
This allows for changing the backlight-brigthness out-of-the-box. Especially on
a terminal (TTY), but also on any other kind of environmnet on top of X11 or
Wayland (i3wm, fluxbox, window-maker...$YOUR_SETUP_HERE).


Thank you
Peter</pre>
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