[SOLVED] Backlight level: kernel parameter to set it

[paskali]

Hi all, i am new on this forum and i am new about TinyCore Linux. Just in these days i am trying it;
however i have a problem which the solution may be good usefull for a lot of you.
OK:
i start TinyCore linux from my dos partition with linld or loadlin. I have an old pentium 3 laptop but that does work very fine for me. Usually i set backilght level at 50/60% and not to 100%, this increase battery life by making screen readable the same; however i make this setting in battery and ac adapter mode, no any difference between them. Anytime Windows XP does start, set backlight to 100% by it self, i had to change the values of two registry keys and now it does not change any more backlight level to 100%. My problem is simple:
what kernel parameter must i use to set backlight level or to not change it? I do not know very well kernel 3 but i think there is an acpi parameter good for my problem.
Therefore i want to make Linux start as well as Windows XP, it have not to change backlight level to 100% but either set it to 50/60% or to keep it at the level setted on BIOS.
Do you understand?
Thanks!

[Rich]

Hi zemir
Try xbacklight, it's in Xorg-7.5-bin.tcz.

[paskali]

Yes, may be a solution but if i use microcore that start console mode (no X) the problem does not resolve in this way. It is indipendent from Xserver, it is a acpi isue, kernel load laptop module and set backlight at 100% because the laptop works with ac adapter. I do not want this, i want that kernel leaves backilght as well as i have setted it.

[paskali]

Hi all, i have solved by starting kernel with this parameter:
laptop acpi_backlight=vendor

[HansJoachmi1]

Hi,
i've tried to start tcl over PXE with Syslinux and the following configuration:

Code: [Select]

LABELTCL
 kernel /kernels/tcl/vmlinuz
 APPEND  laptop acpi_backlight=vendor initrd=/kernels/tcl/core.gz
but it seems it has no effect.
Do I have to recomplile the kernel with the parameters or isnt the Syslinux configuration correct?

best Regards
Joachim

[polikuo]

LABELTCL
 kernel /kernels/tcl/vmlinuz
 APPEND  laptop acpi_backlight=vendor initrd=/kernels/tcl/core.gz

Hi, HansJoachmi1.
You forgot the space between LABEL and TCL:

LABEL TCL   ### with space ###
 kernel /kernels/tcl/vmlinuz
 APPEND  laptop acpi_backlight=vendor initrd=/kernels/tcl/core.gz

I'm not sure if "acpi_backlight=vendor" will work thought.

[Scampada]

Is your question answered yet? I see the [SOLVED] marker above but no corresponding posts below.

If you want to control your backlight brightness level from within console mode try echoing and catting /sys/class/backlight/acpi_video0/brightness.
You can tune brightness level very precisely doing so, and even make it much more dark then any X widget allows.
There are even Fx buttons working for changing brightness level. You only have to have the relevant module loaded.
IIRC it's in graphics-KERNEL-tinycore.tcz.

You can see how I utilized it in my own installation.
https://pp.userapi.com/c626516/v626516354/4fa09/x_UNzNwgJo4.jpg
https://pp.userapi.com/c626516/v626516354/4fa00/T_F5RLxwPIQ.jpg