Cannot increase display brightness with hotkeys

[elyk]

I can no longer increase my screen brightness using the hotkeys. Decreasing brightness works fine, but when I press fn+up the brightness bar increases for a moment, then rapidly returns to its previous position, with no visible change in the display brightness. The brightness panel applet works fine to allow me to change brightness, as does the power management config app. I began to notice this bug when I installed the 9/18 set of updates, having previously updated the evening before.

[Juan Pablo Salazar Bertín (snifer)]

Increasing LCD brightness in 5% steps is not enough for my Dell Inspiron 9400 laptop.

[elyk (elyk53)]

I am also experiencing an inability to decrease brightness to the lowest level.

[Loic Nageleisen (lloeki)]

experiencing it too on a dell xps m1210 with nvidia go7400 and gutsy.

it was working somehow fine before some update around 9/18, and suddently broke. out of the blue I tried downgrading acpi-support and hotkey-setup, since they were part of the update, but no luck.

blacklisting video module makes it hotkey-controllable again, but of course it's not anymore software-controllable.
kernel got updated too around that time, so that may be it.

still, before the update there was another issue, there was a 'double-value' increase and decrease. I mean, when pressing fn+brighter under X, it was setting brightness by a bigger step than under console (i.e bios-controlled). it seems it was raising twice: both software-controlled and bios-controlled on the keypress. thus setting the brightness was imprecise.

[Juan Pablo Salazar Bertín (snifer)]

I see two possible solutions:

1. To change g-p-m so it detects proper brightness steps to increase/decrease.

2. To change acpi video module. This can be:
a) Using real values for brightness levels (0 to 7 instead of 12 to 100 in my case).
b) Changing how intermediate values affect brightness. I mean if I'm at 24, and I try to change to 23 or 25, it should change to the next level (12 or 36) to avoid problems like this.

[nick (kcin1204)]

this is also a problem on the dell m1330 laptop model as well. fn+up does not increase brightness, but fn+down does decrease. Software changes are possible with no irregularities. This change though happened not on 9/18 as previously mentioned but on 9/17´s round of updates.

[Pavel Aleksandrov (afterburner-mail)]

I can confirm this on a Dell Inspiron 6400 (1505). Brightness can go down, but not all the way and when I try to increase it, it just goes up a bit for a second and then returns to the old value. This happens only with the keyboard keys, when I use the Power Management software it all works OK. I am using Gutsy tribe 5 with all available updates installed, upgraded over Feisty.

[elyk (elyk53)]

Here's my output with gnome-power-manager --verbose --no-daemon

[DarkStarSword (darkstarsword)]

Maybe a duplicate/related to bug #140782

[elyk (elyk53)]

This seems separate to me - in that case the keypresses do not seem to have been received at all. In this case, gpm is receiving the keypresses (decrease works fine, and increase still shows the brightness osd), but is not properly increasing the brightness.

[Pavel Aleksandrov (afterburner-mail)]

Yesterday I made a clean install from the latest tribe live cd and the brightness controls worked fine, they also worked from the live cd. Today, after a system update, they were broken again. The same behaviour - down works, up doesn't.

[junk123 (junk123-deactivatedaccount-deactivatedaccount)]

Having this issue on a Dell 9400 also

[Christian Schneiker (chrisschneiker)]

On my XPS M1330 I can't increase nor decrease brightness with the FN keys since an update to kernel-2.6.22-12-generic. When I boot kernel-2.6.22-10 all is working fine.

[Christian Schneiker (chrisschneiker)]

sorry I forgot, it's also in kde with the guidance-power-manager

[Stas Sușcov (sushkov)]

Will the team leave it unchanged in Ubuntu 7.10?

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[Jon Leighton (jonleighton)]

Me too with a Dell Vostro 1500. I've found a workaround by going to System > Preferences > Power Management and moving the brightness slider, which then "resets" the brightness so I can move the slider to my desired brightness level.

[Stas Sușcov (sushkov)]

You can also try as a solution: add to any of the panels the brightness
applet!
Now you're a click far from controlling laptop brightness!
I hope this ain't gonna be left unsolved...
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[DarkStarSword (darkstarsword)]

Can the people experiencing this bug see if the cause is the same as bug #140782 (which is the behaviour those of us using KDE are experiencing) by adding:
blacklist video
to the end of /etc/modprobe.d/blacklist and reboot.
Check the behaviour of the brightness keys before gnome-power-manager starts, after it has started and from outside of X entirely. If the keys work, it would seem to indicate the same cause.

[Stas Sușcov (sushkov)]

Thx!

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[Pavel Aleksandrov (afterburner-mail)]

After blacklisting the video module, brightness control works, but it is not handled now by the gnome-power-manager, because the manager can't get any info about the brightness level (neither the brightness applet, nor the Power Management from the Preferences menu and also when I change the brightness the indicator bar does not appear).

[elyk (elyk53)]

The workaround in: <https://bugs.launchpad.net/ubuntu/+source/gnome-power-manager/+bug/121833/comments/11 > allows both the hotkeys and the software controls (brightness applet, gnome power manager) to work, but it decreases the number of steps, and therefore the level of fine control available via the hotkeys - it goes from high to low in four presses as opposed to the seven or eight previously available with the hotkeys and still available via the brightness applet.

[LEVIS Cyril (atlas95)]

I have the problem too with my xps 1330 but i don't know how to resolv correctly the problem.What is the best solution?
Thanks

[Juan Pablo Salazar Bertín (snifer)]

This has been fixed for me, probably with changes in hal version 0.5.9.1-1ubuntu9.
Please confirm.

[Pavel Aleksandrov (afterburner-mail)]

Yep, fixed for me also. The first two steps don't make any difference in the brightness, but the other 7 (that's how many were there originally on my inspiron 6400) work just fine! Thanks!

[Stas Sușcov (sushkov)]

Not for me.
I've got the the same version and the latest updates, but nothing changed.
I'm on an asus a6m with ubuntu 7.10 amd64 and nvidia go 6100 video card...
:(

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[elyk (elyk53)]

This is fixed for me too - Dell Vostro 1500 with ubuntu 7.10

[Juan Pablo Salazar Bertín (snifer)]

Looks like this has been fixed for Dell laptops. Please reopen if it's not true.

[Stas Sușcov (sushkov)]

If you need any other reports, just ask me. I can't understand why's that so
different in asus and dell notebooks function keys.

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[Stas Sușcov (sushkov)]

Yet another important important upgrade and the problem is still not solved for asus a6m.

[Oliver Grawert (ogra)]

  * debian/patches/95-from-svn-fix-expected-return-types.patch
    backport 2.20.1 fix for incorrect int vs. uint return values,
    fixes a majority of suspend and bringhtness issues with this version.
    incorporates parts of the 73-getbrightness-returns-int.patch.

 -- Oliver Grawert <email address hidden> Fri, 12 Oct 2007 11:21:29 +0200

it should be solved for everyboody who saw the "g_value_set_int: assertion `G_VALUE_HOLDS_INT (value)' failed" errort in the g-p-m output

[Stas Sușcov (sushkov)]

gnome-power-manager --verbose --no-daemon 2>

[Timothy R. Chavez (timrchavez)]

The bug task for the somerville project has been removed by an automated script. This bug has been cloned on that project and is available here: https://bugs.launchpad.net/bugs/1305669