Brightness on Lenovo Thinkpad W510

[atjoslin]

Hi,

I searched and couldn't find anything to help with my problem.

I'm using a Lenovo Thinkpad W510 64-bit with Fedora.

The problem is the brightness only works after a fresh restart. When I first boot up the computer, the brightness buttons work fine. But then if I suspend and resume, I cannot change the brightness from what it was when I last restarted the computer. The on-screen brightness overlay does change fine, but the actual screen brightness doesn't go up or down.

tl;dr:
1. Restart laptop, brightness controls work
2. Go to suspend/standby, resume, brightness controls break until I restart (brightness overlay shows brightness changing, but screen's brightness stays same)

Any ideas to fix? Thanks

[Epixam]

Im not sure what exactly the problem is, as i have a T420 and am having a similar issue. A temporary solution for the problem would be installing "xbacklight"

Its obviously not an end all solution, but i have been trying to find out what the problem is for some time and to no avail, and have been using this solution for the time being

Ex:

xbacklight -set 80

that will set the backlight to 80 pct

[atjoslin]

Hey Epixam, thanks for the reply.

unfortunately, that doesn't work. I installed xbacklight on yum and tried using it with -set but it doesn't do anything.

any other ideas?

[Epixam]

Hmm interesting. run

acpi_listen

and then try your hotkeys.

I image it will register that they are in fact being pressed, but it may not. Im really not sure what your issue is or how to help, im just trying to get as much info out of you as possible so that when someone who knows what they are doing comes around they can more easily recognize your problem

[atjoslin]

I downloaded acpi but it has no --listen option. It's just:

Usage: acpi [OPTION]...
Shows information from the /proc filesystem, such as battery status or
thermal information.

  -b, --battery		battery information
  -i, --details		show additional details if available:
				- battery capacity information
				- temperature trip points
  -a, --ac-adapter		ac adapter information
  -t, --thermal		thermal information
  -c, --cooling		cooling information
  -V, --everything		show every device, overrides above options
  -s, --show-empty		show non-operational devices
  -f, --fahrenheit		use fahrenheit as the temperature unit
  -k, --kelvin			use kelvin as the temperature unit
  -d, --directory <dir>	path to ACPI info (/sys/class resp. /proc/acpi)
  -p, --proc			use old proc interface instead of new sys interface
  -h, --help			display this help and exit
  -v, --version		output version information and exit

By default, acpi displays information on installed system batteries.
Non-operational devices, for example empty battery slots are hidden.
The default unit of temperature is degrees celsius.

Report bugs to Michael Meskes <meskes@debian.org>.

I tried acpi -V and the only thing it says about brightness (I think it's brightness anyway) is:

Cooling 0: LCD 8 of 15

[stevea]

What does executing this as root report ?

for f in $(find /sys -name brightness) ; do echo -n "$f:: "; cat $f; done

[atjoslin]

This shows up:

/sys/devices/platform/thinkpad_acpi/leds/tpacpi::thinklight/brightness:: 0
/sys/devices/platform/thinkpad_acpi/leds/tpacpi::power/brightness:: 0
/sys/devices/platform/thinkpad_acpi/leds/tpacpi::standby/brightness:: 0
/sys/devices/platform/thinkpad_acpi/leds/tpacpi::thinkvantage/brightness:: 0
/sys/devices/pci0000:00/0000:00:03.0/0000:01:00.0/backlight/acpi_video0/brightness:: 15
/sys/devices/pci0000:00/0000:00:1c.1/0000:03:00.0/leds/phy0-led/brightness:: 0
/sys/devices/pci0000:00/0000:00:1c.4/0000:0d:00.0/leds/mmc0::/brightness:: 0
/sys/devices/pci0000:00/0000:00:1c.7/0000:17:00.0/leds/mmc1::/brightness:: 0

So the interesting line looks like it's

/sys/devices/pci0000:00/0000:00:03.0/0000:01:00.0/backlight/acpi_video0/brightness:: 15

When I turn the brightness down with the key for it then change that code again, that line changes to

/sys/devices/pci0000:00/0000:00:03.0/0000:01:00.0/backlight/acpi_video0/brightness:: 13

None of the other lines changed when I turned down the brightness.

[TrickyHarry]

Dear All,

I have been fighting with this for months and most suggestions state along the lines of:-
http://mikesubuntu.com/2010/05/how-i...-keys-working/
:
Edit /etc/X11/xorg.conf
Add the following entry to the section named "Device"
Option "RegistryDwords" "EnableBrightnessControl=1"

Unfortunately I had two sections named "Device", as below. I placed the entry in the first without any effect and then in the second, which now works. I had to re-investigate this fix, because when I booted up my laptop today the screen was "near black" and I was fed up with it.

The instructions may have worked for some people but not for a more complicated configuration

I logged out and back in, no change. Then I tried to change the brightness level and it worked !!! After 3 months of pain.

Thanks Mike !!

<---- Start /etc/X11/xorg.conf section --->

Section "Device"
Identifier "Videocard0"
Driver "nvidia"
#Option "RegistryDwords" "EnableBrightnessControl=1"
EndSection

Section "Device"
Identifier "Device0"
Driver "nvidia"
VendorName "NVIDIA Corporation"
BoardName "Quadro FX 880M"
Option "RegistryDwords" "EnableBrightnessControl=1"
EndSection

<---- End /etc/X11/xorg.conf section --->

================================================== ======

Originally Posted by atjoslin

Hi,

I searched and couldn't find anything to help with my problem.

I'm using a Lenovo Thinkpad W510 64-bit with Fedora.

The problem is the brightness only works after a fresh restart. When I first boot up the computer, the brightness buttons work fine. But then if I suspend and resume, I cannot change the brightness from what it was when I last restarted the computer. The on-screen brightness overlay does change fine, but the actual screen brightness doesn't go up or down.

tl;dr:
1. Restart laptop, brightness controls work
2. Go to suspend/standby, resume, brightness controls break until I restart (brightness overlay shows brightness changing, but screen's brightness stays same)

Any ideas to fix? Thanks