Set brightness with setpci in xfce

[LonelyStar]

Hi,

I have xubuntu installed on a Asus EEE R052C.
The brightness control does not work.
But what I can do is:

sudo setpci -s 00:02.0 f4.b=80

In the console. Ok, but tedious. Can I somehow automate this so that I have an easy control over brightness (preferable the stander xfce brightness panel plugin)?

Thanks!
Nathan

[Toz]

The first thing to try would be to get the brightness keys on your keyboard to work. Have you tried the acpi_backlight=vendor kernel parameter? Here is how:
1. Edit the grub file:

sudo leafpad /etc/default/grub

2. Change the line that reads:

GRUB_CMDLINE_LINUX=""

...to read:

GRUB_CMDLINE_LINUX="acpi_backlight=vendor"

3. Save the file.

4. Update the boot loader:

sudo update-grub

5. Reboot your computer and try again to see if the brightness keys work.


If not, I have a script that can automate the brightness changing, but it will need to be modified to your setup. Can you run the following command and post back the results:

for interface in /sys/class/backlight/*; do echo $interface; cat $interface/max_brightness; cat $interface/actual_brightness; done

^^This command will report back your backlight interfaces and their current values.

[Merrattic]

You can also use xrandr to adjust screen brightness:

xrandr --screen VGA1 --brightness 100

[detronator]

Same problem here on asus notebook..
Update to the grub didn't worked out :/


Result of the command is


/sys/class/backlight/intel_backlight
4296
1728

[Toz]

Same problem here on asus notebook..
Update to the grub didn't worked out :/


Result of the command is


/sys/class/backlight/intel_backlight
4296
1728

Can you provide more info about your system (specifically the model number)?

Also:
1. What video card(s) do you have:

sudo lspci -vnn | grep -A12 VGA

2. The results of the following command after you've tried the acpi_backlight=vendor kernel parameter:

cat /proc/cmdline

[detronator]

sudo lspci -vnn | grep -A12 VGA
Result:
00:02.0 VGA compatible controller [0300]: Intel Corporation 2nd Generation Core Processor Family Integrated Graphics Controller [8086:0106] (rev 09) (prog-if 00 [VGA controller])
Subsystem: ASUSTeK Computer Inc. Device [1043:14f7]
Flags: bus master, fast devsel, latency 0, IRQ 45
Memory at f7800000 (64-bit, non-prefetchable) [size=4M]
Memory at e0000000 (64-bit, prefetchable) [size=256M]
I/O ports at f000 [size=64]
Expansion ROM at <unassigned> [disabled]
Capabilities: [90] MSI: Enable+ Count=1/1 Maskable- 64bit-
Capabilities: [d0] Power Management version 2
Capabilities: [a4] PCI Advanced Features
Kernel driver in use: i915
Kernel modules: i915



cat /proc/cmdline

Result:

BOOT_IMAGE=/boot/vmlinuz-3.5.0-26-generic root=UUID=ce5ed486-4b35-4670-8cfa-cef698edf40f ro acpi_backlight=vendor quiet splash vt.handoff=7



Laptop model is : ASUS X501A, running xubuntu 64bit. CPU is Intel Celeron B830 1.80GHz, VGA is Intel HD Graphics 2000 with 1696MB shared memory

[Toz]

Can you give the following kernel parameters a try instead (remove acpi_backlight). Try them individually:
- acpi_osi=
- acpi_osi=Linux acpi_backlight=vendor

When you've booted with each of these kernel parameters:
1. Post back the results of:

cat /proc/cmdline

2. Post back your dmesg log:

pastebinit /var/log/dmesg

...and paste back the link that is generated.

[detronator]

Ok we have huge success Brightness buttons started working like they should! Thanks very much for the help.

I tried both possible solutions and the first one (GRUB_CMDLINE_LINUX="acpi_osi=") did the job. For testing purposes I tried the other one as well but with no success. Here are both logs, again - for testing purposes :


1) with GRUB_CMDLINE_LINUX="acpi_osi=" (winner!)

cat /proc/cmdline :


BOOT_IMAGE=/boot/vmlinuz-3.5.0-26-generic root=UUID=ce5ed486-4b35-4670-8cfa-cef698edf40f ro acpi_osi= quiet splash vt.handoff=7


pastebinit /var/log/dmesg :


http://paste.ubuntu.com/5633901/




2) with GRUB_CMDLINE_LINUX="acpi_osi=Linux acpi_backlight=vendor"


cat /proc/cmdline :


BOOT_IMAGE=/boot/vmlinuz-3.5.0-26-generic root=UUID=ce5ed486-4b35-4670-8cfa-cef698edf40f ro acpi_osi=Linux acpi_backlight=vendor quiet splash vt.handoff=7


pastebinit /var/log/dmesg :


http://paste.ubuntu.com/5633903/


PS: After I saw that my brightness control slider on the panel was resetting the brightness whenever i click on it, I deinstalled the whole xfce power manager and this fixed an old issue with the brightness resetting on every restart;