Backlight control's not functioning

[DGINSD]

I just installed 13.04 in my HP pavilion G6 about a week ago an I've gotten most everything working now, with the exception of the display backlight. The hot keys will bring up the brightness slider and show it moving but the actual brightness does not change.

Issueing a

[CODE echo 5 | sudo tee /sys/devices/pci0000:00/0000:00:01.0/backlight/acpi_video0/brightness][/CODE]

 echo 1 | sudo tee /sys/devices/pci0000:00/0000:00:01.0/backlight/acpi_video0/brightness

changes the control files just as using the hotkeys does but the brightness doesn't change, this function worked perfectly in 12.04 and 12.10. If I hold the up or down hotkeys eventually brightness will change, so I can achieve my desired brightness by toggling between the setting I want and the one above or below it.

I've also tried adding the grub command line perimeters separately and together

acpi_osi=Linux      acpi_backlight=vendor      acpi_osi=

these also had no effect on the backlight control, but bad effects in other areas. "acpi_osi=" caused the machine not to boot entirely, "acpi_backlight=vendor" caused the hotkeys to not even change the notify slider.

I can't even use use scripts as changing the control files doesn't consistently change the actual brightness. I'm open to any ideas and very much would like to get this fixed

[Toz]

I've also tried adding the grub command line perimeters separately and together

acpi_osi=Linux      acpi_backlight=vendor      acpi_osi=

As a quick first suggestion, can you try the acpi_osi=\"!Windows 2012\" kernel parameter? The relevant entries in /etc/default/grub should look like this:

GRUB_CMDLINE_LINUX_DEFAULT="quiet splash"
GRUB_CMDLINE_LINUX="acpi_osi=\"!windows 2012\""

...(make sure you get the correct number of quote symbols in that last line).

Don't forget to run:

sudo update-grub

...and reboot.

Once rebooted, try the brightness keys again as well as posting back:

cat /proc/cmdline

...and

sudo lspci -vnn | grep -A15 VGA

[DGINSD]

I'll get on it as soon as I get back home to my computer.

I was hoping I'd get a response from you, you seem to be involved in a lot of the threads I found regarding brightness control issues. If I may offer a compliment, you seem to have a lot of good and creative ideas to work around these problems.

[DGINSD]

OK I added the grub command line entry

"acpi_osi=\"!windows 2012\""

and then

sudo update-grub  

sudo reboot

After the reboot the problem persists just as before, no control when the hotkeys are pressed, but if held down change will eventually be made, but this happens with no regularity.

Here is the output of the other two commands

david@HP-G6:~$ cat /proc/cmdlineBOOT_IMAGE=/boot/vmlinuz-3.8.0-26-generic root=UUID=f0ff1ffc-ca4e-416a-b47d-a6b0c7c4bbf0 ro "acpi_osi=!windows 2012" quiet splash vt.handoff=7

david@HP-G6:~$ sudo lspci -vnn | grep -A15 VGA
[sudo] password for david: 
00:01.0 VGA compatible controller [0300]: Advanced Micro Devices [AMD] nee ATI Sumo [Radeon HD 6480G] [1002:9649] (prog-if 00 [VGA controller])
    Subsystem: Hewlett-Packard Company Device [103c:169b]
    Flags: bus master, fast devsel, latency 0, IRQ 45
    Memory at e0000000 (32-bit, prefetchable) [size=256M]
    I/O ports at 4000 [size=256]
    Memory at f0500000 (32-bit, non-prefetchable) [size=256K]
    Expansion ROM at <unassigned> [disabled]
    Capabilities: [50] Power Management version 3
    Capabilities: [58] Express Root Complex Integrated Endpoint, MSI 00
    Capabilities: [a0] MSI: Enable+ Count=1/1 Maskable- 64bit+
    Capabilities: [100] Vendor Specific Information: ID=0001 Rev=1 Len=010 <?>
    Kernel driver in use: fglrx_pci


00:01.1 Audio device [0403]: Advanced Micro Devices [AMD] nee ATI BeaverCreek HDMI Audio [Radeon HD 6500D and 6400G-6600G series] [1002:1714]
    Subsystem: Advanced Micro Devices [AMD] nee ATI BeaverCreek HDMI Audio [Radeon HD 6500D and 6400G-6600G series] [1002:1714]
    Flags: bus master, fast devsel, latency 0, IRQ 44

[Toz]

Oops, my bad. Typo. It should be acpi_osi=\"!Windows 2012\" (note the capital W). Can you try it again?

Also, after reboot, can you show the results of the following command:

for i in /sys/class/backlight/*; do echo $i; cat $i/brightness; cat $i/max_brightness; done

Can I also see your dmesg log file?

pastebinit /var/log/dmesg

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

[DGINSD]

Changed the grub command line parameter and ran update-grub as root, no change in status.

Ran the command you gave and here is the results

david@HP-G6:~$ for i in /sys/class/backlight/*; do echo $i; cat $i/brightness; cat $i/max_brightness; done/sys/class/backlight/acpi_video0
3
10

http://paste.ubuntu.com/5848557/

[DGINSD]

This likely has nothing to do with my backlight issue, or perhaps it does, but one of the lines in the dmesg outputstruck me as odd.

[ 1.275630] powernow-k8: this CPU is not supported anymore, using acpi-cpufreq instead.

On my other partition/install I had a script to change and adjust the CPU governor, and part of making the script work required loading the "powernow-k8"
module, by adding it to the /etc/modules file. I hadn't tried using the set up on this install, as it seems much more efficient and doesn't seem to need it.

Just something that caught my eye, and perhaps totally irrelevant, but maybe a clue to a larger more general issue of my system configuration not 100% as it should be.

[Toz]

Changed the grub command line parameter and ran update-grub as root, no change in status.

Ran the command you gave and here is the results

david@HP-G6:~$ for i in /sys/class/backlight/*; do echo $i; cat $i/brightness; cat $i/max_brightness; done/sys/class/backlight/acpi_video0
3
10

http://paste.ubuntu.com/5848557/

From your dmesg log file:

[ 0.230803] [Firmware Bug]: ACPI: No _BQC method, cannot determine initial brightness
[ 0.231051] [Firmware Bug]: ACPI: No _BQC method, cannot determine initial brightness
[ 0.231309] [Firmware Bug]: ACPI: No _BQC method, cannot determine initial brightness

Can you try the kernel parameters acpi_osi=Linux acpi_backlight=vendor again and after reboot, post back again:

pastebinit /var/log/dmesg

...and

for i in /sys/class/backlight/*; do echo $i; cat $i/brightness; cat $i/max_brightness; done

[DGINSD]

Ok this time I get no brightness change or notification with the up or down hotkeys. Also now in system settings, brightness & lock, there is no brightness slider.

The pastebin link http://paste.ubuntu.com/5850249/

The output of the command given

david@HP-G6:~$ for i in /sys/class/backlight/*; do echo $i; cat $i/brightness; cat $i/max_brightness; done/sys/class/backlight/*
cat: /sys/class/backlight/*/brightness: No such file or directory
cat: /sys/class/backlight/*/max_brightness: No such file or directory

[dino99]

This is fixed upstream in the 3.10-rc4 kernel by this commit:

author Ash Willis 2013-05-29
committer Rafael J. Wysocki 2013-06-01
commit 780a6ec640a3fed671fc2c40e4dd30c03eca3ac3

ACPI / video: ignore BIOS initial backlight value for HP Pavilion g6

https://bugs.launchpad.net/ubuntu/+s...l/+bug/1173059
http://ubuntu.5.x6.nabble.com/3-8-y-...td5028617.html