HP Laptop dv6-6195ca + Ubuntu 11: brightness problem

[hp6195]

I am having a problem with the brightness control on my HP dv6-6195ca laptop. I've been fiddling with this for hours now to no avail.

The F2/F3 keys are recognized in Ubuntu 11.04 and I see the popup showing the brightness increasing and decreasing, but it has no effect on the screen.

I've looked around and a lot of threads suggest working with /proc/acpi/video/VGA/LCD/brightness, but I don't have a video directory under /proc/acpi.

/proc/acpi$ ls -l
total 0
dr-xr-xr-x 3 root root 0 2011-10-04 19:06 ac_adapter
dr-xr-xr-x 3 root root 0 2011-10-04 19:06 battery
dr-xr-xr-x 4 root root 0 2011-10-04 19:06 button
-r-------- 1 root root 0 2011-10-04 19:01 event
-rw-r--r-- 1 root root 0 2011-10-04 19:06 wakeup

lspci output:

$ lspci
00:00.0 Host bridge: Intel Corporation 2nd Generation Core Processor Family DRAM Controller (rev 09)
00:01.0 PCI bridge: Intel Corporation 2nd Generation Core Processor Family PCI Express Root Port (rev 09)
00:02.0 VGA compatible controller: Intel Corporation 2nd Generation Core Processor Family Integrated Graphics Controller (rev 09)
00:16.0 Communication controller: Intel Corporation 6 Series Chipset Family MEI Controller #1 (rev 04)
00:1a.0 USB Controller: Intel Corporation 6 Series Chipset Family USB Enhanced Host Controller #2 (rev 05)
00:1b.0 Audio device: Intel Corporation 6 Series Chipset Family High Definition Audio Controller (rev 05)
00:1c.0 PCI bridge: Intel Corporation 6 Series Chipset Family PCI Express Root Port 1 (rev b5)
00:1c.1 PCI bridge: Intel Corporation 6 Series Chipset Family PCI Express Root Port 2 (rev b5)
00:1c.2 PCI bridge: Intel Corporation 6 Series Chipset Family PCI Express Root Port 3 (rev b5)
00:1c.3 PCI bridge: Intel Corporation 6 Series Chipset Family PCI Express Root Port 4 (rev b5)
00:1d.0 USB Controller: Intel Corporation 6 Series Chipset Family USB Enhanced Host Controller #1 (rev 05)
00:1f.0 ISA bridge: Intel Corporation HM65 Express Chipset Family LPC Controller (rev 05)
00:1f.2 SATA controller: Intel Corporation 6 Series Chipset Family 6 port SATA AHCI Controller (rev 05)
00:1f.3 SMBus: Intel Corporation 6 Series Chipset Family SMBus Controller (rev 05)
01:00.0 VGA compatible controller: ATI Technologies Inc Device 6740
07:00.0 Ethernet controller: Realtek Semiconductor Co., Ltd. RTL8111/8168B PCI Express Gigabit Ethernet controller (rev 06)
0d:00.0 Network controller: Intel Corporation Centrino Wireless-N 1030 (rev 34)
13:00.0 Unassigned class [ff00]: Realtek Semiconductor Co., Ltd. Device 5209 (rev 01)
19:00.0 USB Controller: NEC Corporation uPD720200 USB 3.0 Host Controller (rev 04)

It appears that everything is working in Ubuntu, but I suspect that the brightness setting is not being sent to the hardware. When I turn the brightness up and down, it is being registered:

Full brightness:

$ cat /sys/devices/virtual/backlight/acpi_video0/brightness
10
$ cat /sys/devices/virtual/backlight/acpi_video1/brightness
10

Lowest brightness:

$ cat /sys/devices/virtual/backlight/acpi_video0/brightness
0
$ cat /sys/devices/virtual/backlight/acpi_video1/brightness
0


Any suggestions?

[Toz]

Hello and welcome to the forums.

Have you tried booting with the kernel parameters acpi_osi=\\"Linux\\" acpi_backlight=vendor ?

You might be able to manually manipulate the brightness via:

echo "50" | sudo tee /sys/devices/virtual/backlight/acpi_video0/brightness

...or

xrandr --output LVDS --brightness 0.5

("xrandr -q" will help identify the name of the display if LVDS is incorrect)
...or

sudo setpci -s 01:00.0 F4.B=7F

[Kobnar]

Hey there! I'm jumping in on this one because it's really starting to nag me.

I have an HP dv6 with intel/Radion 6700M graphics and a backlight issue that I had fixed for a few blissful weeks - and then something changed and all of a sudden it doesn't work.

For those few blissful weeks, however, this is what I did:

Edit the grub config file...

$ sudo /etc/default/grub

Add the following to GRUB_CMDLINE_LINUX_DEFAULT=""...

acpi_osi=Linux acpi_backlight=vendor

Save and quit.

Reconfigure the grub bootloader...

$sudo update-grub

Reboot.

Hopefully that helps! Maybe with a bit of karma somebody will help me.

Not to hijack your thread but that's what I did and it worked for a while until some update I wasn't tracking suddenly broke it. No matter what I do now, I can't change my brightness.

Any tips?

[Toz]

@Kobnar, what do you have in your /sys/class/backlight directory?

ls -l /sys/class/backlight

...and

ls -l /sys/devices/virtual/backlight

Also, what does

lsmod

return?

Have you tried the codes from post #2 to see if they work?

[Kobnar]

Sorry for the late reply :/ I thought I was subscribed to this thread but apparently I wasn't.

I still have no backlight control via function keys. To change the brightness, I have to manually enter:

echo 1000 | sudo tee /sys/class/backlight/intel_backlight/brightness

That drops it down to about 50% brightness. (the xrandr settings just change the color brightness and have no effect on the actual backlight.)

Preferably, I would like to get the buttons working again. I've read around and this is all apparently because HP uses a funky ACPI.

A strange side-effect of all this is that if I leave my computer sitting for about 10 minutes, the screen goes blank and there's no way for me to get it back without unplugging it and closing the lid to force the power manager to kick it into sleep. (upon immediately opening the lid, the brightness is reset and I can see my screen again)

[dansk]

Just thought I'd bump this up. I'm using Lubuntu 11.10 on an HP dv6-6195ca and having the same problems as the other fine people in this thread. Anyone had any insight into this recently?

[dansk]

Just an update:

I'm having precisely the same issues as everyone else here, in the same order as them. Adding the 'acpi_backlight=vendor' line in grub fixed the problem for me for about two days, but inexplicably quit working.

Echoing brightness values directly to /sys/class/backlight/intel_backlight/brightness works, but it's clumsy and I'd rather find a permanent fix for this.

is there any way to find out exactly what output is coming from the function keys?

[Toz]

Just an update:

I'm having precisely the same issues as everyone else here, in the same order as them. Adding the 'acpi_backlight=vendor' line in grub fixed the problem for me for about two days, but inexplicably quit working.

Echoing brightness values directly to /sys/class/backlight/intel_backlight/brightness works, but it's clumsy and I'd rather find a permanent fix for this.

is there any way to find out exactly what output is coming from the function keys?

What is your current kernel command line?

cat /proc/cmdline

Have you tried these variations?
- acpi_osi=
- acpi_osi=Linux
- acpi_osi="Linux"
- acpi_osi=Linux acpi_backlight=vendor
- acpi_osi= acpi_backlight=vendor

[dansk]

What is your current kernel command line?

cat /proc/cmdline

BOOT_IMAGE=/boot/vmlinuz-3.0.0-16-generic root=UUID=be44ff56-60d6-40dd-9013-8036b48a58b5 ro quiet splash acpi_osi=Linux vt.handoff=7

Have you tried these variations?
- acpi_osi=
- acpi_osi=Linux
- acpi_osi="Linux"
- acpi_osi=Linux acpi_backlight=vendor
- acpi_osi= acpi_backlight=vendor

I tried all of them and no dice.

[Toz]

BOOT_IMAGE=/boot/vmlinuz-3.0.0-16-generic root=UUID=be44ff56-60d6-40dd-9013-8036b48a58b5 ro quiet splash acpi_osi=Linux vt.handoff=7

Try again with acpi_backlight=vendor and post back the results of the following commands:

cat /proc/cmdline
lsmod
ls /sys/class/backlight
sudo lspci -vnn | grep -A10 VGA
cat /var/log/syslog | grep -i acpi

EDIT: Can you also try these two parameters?
- acpi_osi=\\"Linux\\"
- acpi_osi=\\"Linux\\" acpi_backlight=vendor