Brightness adjustment problem for Toshiba L500D

[cogitator]

I upgraded to Lubuntu 12.04, everything seems okay until now, except that I can not set the backlight of my (laptop's) monitor screen (for example, "xbacklight -set 50" does not make any effect, nor using the FN+F6 or FN+F7 keys does something). In 11.10 it was okay, but now (in 12.04) is not. [My eyes hurts...!]

I'll appreciate any advice. Thanks in advance.


P.S.#1: Also, a minor problem (maybe) is that the temperature goes up very quickly now (with 12.04, this didn't happen with 11.10) and so the cooling fan work more fast and, that means that more energy it consumes.

P.S.#2: This is my worst experience in Ubuntu until now.

[cogitator]

There should be a solution. I really can not comfortably use my pc with that problem in Lubuntu 12.04. All that strong light ...it is like being in a solarium! [There is a solution... to wear sunglasses, how's that...? Just kidding... but, really, you can not tolerate that.]

Well, if you are willing to help, do so -for the sake of Ubuntu.

[brainwash]

Did you already tell your system to use the vendor-specific driver for the backlight by adding acpi_backlight=vendor to the kernel parameter list (grub2)? There are also other ways to adjust screen brightness, for example:

sudo setpci -s 00:02.0 F4.B=XX

XX is the desired brightness in hexadecimal ranging from 00 to FF.

FF = 100%
7F = 50%
00 = 0%

You might need to change the hardware address (00:02.0). To get the correct one, check the output of this command:

lspci | grep VGA

[cogitator]

Hi "brainwash", I have already tell my system to use this, but it did not change anything and still I can not change the brightness. But thank you for the additional information about this way to adjust the brightness, it may be useful in some other occasion.

All that means that I am going back to Lubuntu 11.10 and, so my computer will be able to wake up from this 12.04 nightmare... I hope that this situation will change in the near future.

Okay, bye-bye 12.04, before the cpu will melt, too...

[Toz]

What is the make/model of your computer? Sometimes, adding

acpi_osi=Linux acpi_backlight=vendor

...to the grub kernel line will fix issues like this one. But it depends on your computer.

[cogitator]

Hi "Toz". The model of my computer is: Toshiba Satellite L500D

[Toz]

Did you try those kernel parameters from post #5? See here for information on how to test it.

If still no luck, open a terminal window, type in the following commands, and post back the results:

cat /proc/cmdline
ls /sys/class/backlight/*/
sudo lspci -vnn | grep -A10 VGA

[cogitator]

Hello (again), Toz. I delayed to post a new reply in this thread, because I went back at Lubuntu 10.04 (specifically "Peppermint 2") and there I did not have any problem with the brightness of my monitor. But now that I installed "Peppermint 3" and thus Lubuntu 12.04, the problems did come again. I tried those kernel parameters from post#5, but they did not have any effect. So, I typed in the suggested commands and, here are the results:

"cat /proc/cmdline":
BOOT_IMAGE=/boot/vmlinuz-3.2.0-29-generic-pae root=UUID=b1834d50-6d96-4c36-9e52-05cfbeeab5c6 ro quiet splash vt.handoff=7

"ls /sys/class/backlight/*/":
/sys/class/backlight/acpi_video0/:
actual_brightness  brightness  max_brightness  subsystem  uevent
bl_power           device      power           type

/sys/class/backlight/toshiba/:
actual_brightness  brightness  max_brightness  subsystem  uevent
bl_power           device      power           type

"sudo lspci -vnn | grep -A10 VGA":
02:00.0 VGA compatible controller [0300]: Advanced Micro Devices [AMD] nee ATI RV710 [Mobility Radeon HD 4500/5100 Series] [1002:9553] (prog-if 00 [VGA controller])
    Subsystem: Toshiba America Info Systems Device [1179:ff80]
    Flags: bus master, fast devsel, latency 0, IRQ 45
    Memory at d0000000 (32-bit, prefetchable) [size=256M]
    I/O ports at 9000 [size=256]
    Memory at cfef0000 (32-bit, non-prefetchable) [size=64K]
    [virtual] Expansion ROM at cfe00000 [disabled] [size=128K]
    Capabilities: [50] Power Management version 3
    Capabilities: [58] Express Legacy Endpoint, MSI 00
    Capabilities: [a0] MSI: Enable+ Count=1/1 Maskable- 64bit+
    Capabilities: [100] Vendor Specific Information: ID=0001 Rev=1 Len=010 <?>

[Toz]

Hi.
You're cmdline doesn't have "acpi_osi=Linux acpi_backlight=vendor" added to it. Make sure it was properly tested.

1. Edit /etc/default/grub:

gksu leafpad /etc/default/grub

2. Replace the line that reads:

GRUB_CMDLINE_LINUX=""

...with:

GRUB_CMDLINE_LINUX="acpi_osi=Linux acpi_backlight=vendor"

3. Save the file.

4. Update grub:

sudo update-grub

5. Reboot and test. Double-check command line with:

cat /proc/cmdline

...again to make sure it is there.

-----------------------

If it still doesn't work, have you installed the proprietary driver for your ATI video card?

-----------------------

If the first thing didn't work, can you post back the results of this command:

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

[cogitator]

After the application of all the steps from 1 to 5, now the FN+F6 or FN+F7 keys does not working at all.

"cat /proc/cmdline":
BOOT_IMAGE=/boot/vmlinuz-3.2.0-29-generic-pae root=UUID=b1834d50-6d96-4c36-9e52-05cfbeeab5c6 ro acpi_osi=Linux acpi_backlight=vendor quiet splash vt.handoff=7

After the application, I also installed the proprietary driver for my ATI video card, but nothing changed.

Here are the results of the below suggested command:

"for i in /sys/class/backlight/*; do echo $i; cat $i/max_brightness; cat $i/actual_brightness; cat $i/brightness; done":
/sys/class/backlight/*
cat: /sys/class/backlight/*/max_brightness: Δεν υπάρχει τέτοιο αρχείο ή κατάλογος
cat: /sys/class/backlight/*/actual_brightness: Δεν υπάρχει τέτοιο αρχείο ή κατάλογος
cat: /sys/class/backlight/*/brightness: Δεν υπάρχει τέτοιο αρχείο ή κατάλογος

Note: "Δεν υπάρχει τέτοιο αρχείο ή κατάλογος"(Greek) = "No such file or directory".