Brightness control
I have an Acer ASPIRE M5 481T and can't adjust the screen brightness. It came with windows 8 pre-installed which I removed.
I used xbacklight and got "No outputs have backlight property"
Tried "setpci -s 00:02.0 f4.b=XX" without success.
Also changed the bootloader parameters with "acpi_backlight=vendor" and didn't work.
What can I do? Thank you.
On Sun, 17 Nov 2013 11:06:43 +0100 (CET)
x@x wrote:
> I have an Acer ASPIRE M5 481T and can't adjust the screen brightness.
> It came with windows 8 pre-installed which I removed.
>
> I used xbacklight and got "No outputs have backlight property"
>
> Tried "setpci -s 00:02.0 f4.b=XX" without success.
>
> Also changed the bootloader parameters with "acpi_backlight=vendor"
> and didn't work.
>
> What can I do? Thank you.
I used to have that problem with my notebook, but after I installed the
Linux-libre kernel, the brightness adjustment worked. However, it may
or may not work on your Acer. I suggest you try it out.
Here are the instructions on how to do it.
http://jxself.org/linux-libre/
I am a member!
You can also try this which worked with my Asus Eee PC 1005PE:
Modify your /etc/default/grub configuration file to include acpi_osi=Linux parameter on the GRUB_CMDLINE_LINUX_DEFAULT line and reboot. So, if it looks like this:
GRUB_CMDLINE_LINUX_DEFAULT="quiet splash"
Make it look like this:
GRUB_CMDLINE_LINUX_DEFAULT="quiet splash acpi_osi=Linux"
Could you also add your laptop to www.h-node.org, please? It would help a lot especially if your laptop works fine with free software. Add a notice to the description about the screen brightness problem and a solution if you found one.
Please add your laptop even if it does not work well with free software. Devices like that are important to report so that others can avoid them.
Hi blackomegarey and lammi87, thank you for your time. I installed the linux-libre kernel and put the acpi_osi=Linux parameter on grub and didn't solve the problem.
I've just registered my laptop at h-node.org
I am a member!
Sorry to hear the brightness problem is still bothering you. Try to search a similar laptop models from h-node and see if they have any entries about similar problem. This problem might have been solved already.
Anyway, thanks a lot for contributing to h-node! By the way, next time please register an account to h-node and log in before making a contribution. That way, admins don't have to approve your entries and they will be added to the database right away.
As an admin, I can see that you did not specify some important details like how the videocard works, what are the model names of your video and wifi cards and the webcam and what kernel version did you use. Could you please add them? I have approved your device entry for now.
You can find the instructions about how to find the details I asked from h-node's wiki (http://h-node.org/wiki/page/en/Discover-your-hardware). You need to just use the commands lspci, sudo lspci -vmmnn, sudo lspci -nnk and sudo lsusb -v. It is not difficult. Again, thanks for your contribution.
PS I'm quite sure your laptop won't have free boot firmware. Basically if it has coreboot then it does have one. Could you also check this? If you have UEFI or BIOS, then it most likely is not free.
I am a member!
I went and checked all the aspire models on h-node and found this:
"Append acpi_backlight=vendor to GRUB_CMDLINE_LINUX_DEFAULT. Then run sudo update-grub."
Basically, try adding "acpi_backlight=vendor" to the GRUB_CMDLINE_LINUX_DEFAULT this time. This advice was found on Aspire V5-471's entry details. This model has been commercialized in 2012 according to h-node.
Hey lammi87, you were right about my bios being not free, I corrected it. I was in a rush and filled the form really quickly, also forgot to check if I was logged in.
I already tried appending acpi_backlight=vendor but it didn't work. I also can't run 3D acceleration(can't run compiz, also tried some games), even though it's not a problem for me.
I am a member!
Thanks for your additions!
Regarding your screen brightness problem, I'm almost out of ideas. However, I found this on Arch user foorums (link: https://wiki.archlinux.org/index.php/Backlight#Backlight_utilities):
"All methods expose themselves to the user by /sys/class/brightness. And xrandr/xbacklight could use this folder and choose one method to control brightness. But it is still not very clear which one xbacklight prefers by default. See FS#27677 for xbacklight, if you get "No outputs have backlight property." There is a temporary fix if xrandr/xbacklight does not choose the right directory in /sys/class/brightness: You can specify the one you want in xorg.conf by setting the "Backlight" option of the Device section to the name of that directory (see http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=651741 at the bottom of the page for details). "
Would this help? Try changing this default folder for xbacklight and then make keyboard short cuts for
xbacklight -inc X
xbacklight -dec X
where X is a percentage value so you can increase and decrease the brightness.
