GNOME Bugzilla – Bug 722131
No way to control default screen brightness after power profile change
Last modified: 2014-05-19 12:52:45 UTC
I'm running up-to-date F20 on my Lenovo T520. In the Power module in Settings, I have my brightness set to near maximum, and dim screen when inactive off. When I undock my laptop, the brightness drops to minimum, and I have to bump it up to near max to be comfortable. That's aggravating, but fairly common to see in an OS these days (although at least in Windows versions I'm familiar with, something that's configurable under power profiles). I'd love to be able to set what that brightness it drops down to is, or even if it does at all. If I could manually tell it to be 30% or 50% instead of the 10 or 15% or whatever it is today, it would actually be useful. But as implemented, it takes me more time to up the brightness to what I want than it would to reduce it to what I want from what it originally was before I went to battery usage. What really confuses me though, is when I put my laptop back on a docking station. When I undock, the brightness drops, fine, I'm on battery, it has good intentions, however, when I re-dock... the brightness drops to the same on-battery value! If I'm plugged into the wall, it doesn't seem like there's any reason it should drop brightness back to near minimum. I'm hoping that's a bug. Even if I've readjusted my brightness back to where I want after undocking, when I redock, I just lost that brightness setting, and now my laptop is sitting in a holder that covers the keyboard, so the only way to adjust it back up is to use the brightness slider or go into the power module in settings, I can't access the keyboard on the laptop, and I can't change it from my desktop keyboard. Overall, the power settings seem really limited, to have it be a hard % can't work very well across different laptop models and manufacturers, each laptop has a different display scale, so one may go completely blank and turn off the backlight completely, but another may still be fairly visible. Also, brightness is a very subjective setting, depending on both their current environment, how much battery they have left, and their general preference. Hard coding it to a random value seems unfriendly.
There's nothing in gnome-settings-daemon changing the dim level when plugging in to the dock, or removing it from the dock. This must be something that the firmware does. This isn't gnome-settings-daemon's work. $ gsettings get org.gnome.settings-daemon.plugins.power idle-brightness 30 This is the percentage value that it sets as the brightness when dimming. It will only dim when "Dim screen when inactive" is selected. Try disabling the power plugin if you think it's gnome-settings-daemon's problem: gsettings set org.gnome.settings-daemon.plugins.power active false
*** Bug 730310 has been marked as a duplicate of this bug. ***
(In reply to comment #1) > There's nothing in gnome-settings-daemon changing the dim level when plugging > in to the dock, or removing it from the dock. This must be something that the > firmware does. This isn't gnome-settings-daemon's work. Hm. Have ideas how to fix this?
(In reply to comment #1) > There's nothing in gnome-settings-daemon changing the dim level when plugging > in to the dock, or removing it from the dock. This must be something that the > firmware does. This isn't gnome-settings-daemon's work. > > $ gsettings get org.gnome.settings-daemon.plugins.power idle-brightness > 30 > > This is the percentage value that it sets as the brightness when dimming. It > will only dim when "Dim screen when inactive" is selected. > > Try disabling the power plugin if you think it's gnome-settings-daemon's > problem: > gsettings set org.gnome.settings-daemon.plugins.power active false Ok. I'll try this. Ignore previous comment.
(In reply to comment #1) > gsettings set org.gnome.settings-daemon.plugins.power active false this not fixed my bug. when plug or unplug AC - backlight changing to maximum.
(In reply to comment #5) > (In reply to comment #1) > > gsettings set org.gnome.settings-daemon.plugins.power active false > > this not fixed my bug. when plug or unplug AC - backlight changing to maximum. Well, I'm glad. This means that gnome-settings-daemon isn't responsible for the backlight changing, so it's likely something that knows about both the backlight and the power status changing the backlight. The only thing I can think of on a modern GNOME desktop is the firmware. Please file a bug against the kernel at bugzilla.kernel.org and CC: me on it. Hopefully the kernel can mitigate the problem, most likely by disabling that "feature".
Kernel bug is at: https://bugzilla.kernel.org/show_bug.cgi?id=76491