# desktop brightness not working on laptop



## fluca1978 (Nov 17, 2011)

Hi all,
I'm running PcBSD9 but I've got a problem with KDE and my laptop and I did not find yet a solution on the PCBSD forums, sorry to _cross-post_ here.

I'm running 9 rc-1, which is a FreeBSD 9 rc-1 shipped with KDE, on an Acer Aspire 6935. The screen is really dark, making it difficult to work with the laptop. I've tried to change the screen brightness using the slider that appears in the power manager, but the screen did not change at all. I've then tried to use the *nvidia-settings* utility but while I can adjust gamma, saturation, etc., the brightness does not get changed in any way. Please note that the screen is actually working, since the machine is dual boot and the other OS can correctly adjust brightness.

I've also noted that the screen slightly becomes even darker when I plug the power supplier, and become slightly more bright when I unplug it. This is strange, since I would expect the opposite. The video card is GeForce 9600M GT and the screen is a Seiko/Epson (DFP-0). Anybody has experienced a similar problem and/or has clue or something else I can check on my system to get rid of this problem?


----------



## SirDice (Nov 17, 2011)

See if loading acpi_video(4) helps.


----------



## DutchDaemon (Nov 17, 2011)

Settings made in *nvidia-settings* must be loaded into X, or they will simply not exist. In my case, I load them when I start X (using  *startx*, using this line in .xinitrc:


```
/usr/local/bin/nvidia-settings --load-config-only &
```

This probably needs to be in some other file when starting X differently.


----------



## fluca1978 (Nov 17, 2011)

I've tried loading acpi_video() with kdlload but nothing changed. Then I placed the loading rule in the loader.conf file and rebooted. As the machine restarted I checked with *kldstat* that the module was loaded, but again, nothing changes the brigthness (or I should say the darkness) of the video. I've also tested the gnome desktop, and there the brigtness applet has even a fancy behavior: it cannot be clicked at all since it refuses to move the slider!

By the way, I also noted that Gnome and GDM have a lighter sreen, and even KDE has it when it starts, but after the splash screen disappears it becomes darker. I'm not sure I've understood the loading of nvidia-settings, since the utility allows me to interactively change settings and test them "live", and all settings are changing the screen properties except for brightness. So I guess it should not be a problem of how nvidia-settings are loaded, but I admit I'm lost!:\


----------



## DutchDaemon (Nov 17, 2011)

Settings made in *nvidia-settings* are not retained across restarts of the X server.

[cmd=]man nvidia-settings | less -p"   3. Loading Settings Automatically"[/cmd]


----------



## zeissoctopus (Nov 18, 2011)

Please check the output of the following command after loading acpi_video

```
sysctl -a | grep hw.acpi.video
```


----------



## fluca1978 (Nov 18, 2011)

May it be there is something wrong with the way I load the module?




```
# kldstat | grep acpi | grep video
10    1 0xffffffff8167e000 6d18     acpi_video.ko
```

but the only sysctl I have is


```
# sysctl -a | grep acpi | grep video
hw.acpi.reset_video: 0
```

I load it at boot time with


```
# grep acpi /boot/loader.conf
acpi_video_load="YES"
# Disable acpi throttle by default, fixes issues with powerd and later AMDs
hint.acpi_throttle.0.disabled="1"
```

and I checked that even setting a different brigthness with the nvidia utility and then restarting the system did not change anything.
Am I doing something wrong?


----------



## zeissoctopus (Nov 19, 2011)

fluca1978 said:
			
		

> May it be there is something wrong with the way I load the module?



No, you are correct.

The acpi_video.ko does not support your computer.


----------



## fluca1978 (Nov 19, 2011)

I suppose there is no way to make it working on my laptop. It is very difficult to work with such a screen....


----------



## fluca1978 (Nov 22, 2011)

I've found and tried also the option about the brightness in the x config file:


```
Option "RegistryDwords" "EnableBrightnessControl=1"
```

but nothing has changed at all. I don't want to give up, but I guess there is nothing more to do....suggestions are welcome!


----------



## fluca1978 (Nov 23, 2011)

I've seen on the nvidia site that there is a new driver for FreeBSD released on November, could it be worth a try or my problem does not depend on the GPU driver?


----------



## fluca1978 (Nov 23, 2011)

Arghh!! No luck at all:


```
In file included from nvidia_ctl.c:14:
nv-freebsd.h:25:2: error: #error This driver does not support FreeBSD 9.x/-CURRENT!
*** Error code 1

Stop in /usr/home/luca/Downloads/NVIDIA-FreeBSD-x86_64-290.10/src.
*** Error code 1
```

cause by:


```
#if __FreeBSD_version >= 900000
#error This driver does not support FreeBSD 9.x/-CURRENT!
#endif
```


----------



## fluca1978 (Nov 29, 2011)

A quick update, in the case someone has an hint: I noted that if I start the laptop using the battery the screen remains dark, while if I start it again with the power supplier plugged-in the screen is brighter. So it seems a startup initialization of the screen.


----------



## michaelp (Feb 8, 2012)

I have sort of the same issue although I have full brightness. if I boot from battery it is darker and to brighten the display I have to re-boot with the power plugged in. No sense trying to use the Gnome Brightness Applet, it'll not work. I have tried it with Linux and pc-bsd with no success, when I go to grab the slider it just goes away. I offered no help I just realized


----------



## fluca1978 (Feb 9, 2012)

That is exactly what I'm experiencing: it seems the brightness is set up at the system boot (bios?) and then FreeBSD keeps such value making it impossible to modify it.


----------



## da1 (Feb 9, 2012)

Try:

```
Option "RegistryDwords" "EnableBrightnessControl=1"
```
 in the 
	
	



```
Section "Device"
```
Naturally, X restart is required.


PS: make sure you are using the nvidia driver.


----------



## fluca1978 (Feb 15, 2012)

da1 said:
			
		

> Try:
> 
> ```
> Option "RegistryDwords" "EnableBrightnessControl=1"
> ...



I've already tried, as reported in my previous post #19, but nothing changed. What is the difference (if any)?


----------

