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I followed this tutorial to set the brightness indicator on Unity. But when I run the

sudo /opt/indicator-brightness/

command from a terminal, I get

( Gtk-WARNING **: Impossible to find the theme engine in module_path : « pixmap »
Traceback (most recent call last):

  File "/opt/indicator-brightness/", line 78, in <module>

  File "/opt/indicator-brightness/", line 46, in create_menu
    curr_brightness = get_curr_brightness()

  File "/opt/indicator-brightness/", line 33, in get_curr_brightness

    curr_brightness = int(p.communicate()[0])

ValueError: invalid literal for int() with base 10: 'No backlights were found on your system\n'


Any suggestion is most welcome.

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That tutorial links to some random deb on the internet (you shouldn't trust posts like that), so it's likely that deb is out of date.

Instead try installing it from the developer's PPA and see if you get the error still. If you still do then you need to file a bug on that page with the brightness-indicator developers so they can see if it's a code problem.

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Thanks you very much. That is really helpful. I am on it and give you a feedback when I am done – Alexandre Bourlier Jan 4 '12 at 1:05

This command works for me. I'm too lazy to install things. Hope this helps.

sudo setpci -s 00:02.0 F4.B=50
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