Overview: The brightness controls do not work, either from the keyboard, or the slider in the KDE Power Management Module. Steps to Reproduce: Turn on computer - brightness controls are working at Grub Boot Loader Start Linux - brightness controls have no effect. Platform: Opensuse 11.2 RC-2 Additional Information: This may well be the same as Bug 13121. However, when I tried using patch-13121-4 from comment #41 in that bug, replacing the DMI_BOARD_VENDOR and DMI_PRODUCT_NAME with those from my dmidecode (attached), I got the error: "Hunk #1 FAILED at 586"
Created attachment 23666 [details] dmidecode output from this machine
Will you please attach the output of acpidump, lspci? Will you please check whether there exists backlight interface under the /sys/class/backlight/? For example: acpi_video0 .If it exists, please check whether the brightness can be changed by using the following command: >echo 5 > /sys/class/backlight/acpi_video0/brightness Thanks
Created attachment 23675 [details] acpidump emachine D725 Thanks so much for the help. acpidump and lispci are attached. acpidump also gave error messages (attached). /sys/class/backlight/acpi_video0/ does exist. It's a symbolic link to /devices/virtual/backlight/acpi_video0 Trying the command: >echo 5 > /sys/class/backlight/acpi_video0/brightness nothing happens.This is also true for echo 0-9. However, if I echo 10 or more, I get an error message: "bash: echo: write error: Invalid argument"
Created attachment 23676 [details] LSPCI: emachine D725
Created attachment 23677 [details] Error messages from the acpidump
it seems that ACPI backlight control fails to work for your laptop. what if you boot with "acpi_backlight=vendor"?
With "acpi_backlight=vendor" there are some changes, although neither keyboard, nor brightness slider in kde control panel, nor writing to brightness from the terminal has any effect. The change is that the symlink to acpi_video0 is replaced with acer-wmi (the actual location is ../../devices/platform/acer-wmi/backlight/acer-wmi). The contents of this directory are also different. There are 5 files: - actual_brightness - bi_power - brightness - max-brightness - uevent Also 3 sub-directories: - device (actually a symlink to ../../acer-wmi) - power - subsystem (symlink to ../../../../../class/backlight) It occurred to me that writing to "actual_brightness" might work, but I got a "Permission denied" error, and, checking the properties, found that file is read-only, even for root. Do you need either an acpidump or lspci while the machine is in this state? BTW, one thing possibly worth mentioning is that I can get the keyboard to control brightness by booting with "acpi=off". Of course that's not a very acceptable work-around because I lose battery monitoring.
(In reply to comment #7) > > It occurred to me that writing to "actual_brightness" might work, but I got a > "Permission denied" error, and, checking the properties, found that file is > read-only, even for root. > No, you should poke the "brightness" file instead. please try "echo xxx > /sys/class/backlight/acer_wmi/brightness" and see if the backlight is actually changed. > Do you need either an acpidump or lspci while the machine is in this state? > no. :)
(In reply to comment #8) Thank you for your help. > please try "echo xxx > /sys/class/backlight/acer_wmi/brightness" and see if > > the backlight is actually changed. I tried this and the outcome is the same as before: Nothing happens with echo values of 0-9. With values of 10 or more,I get an error message: "bash: echo: write error: Invalid argument" Just out of curiosity, can you tell me a command to find out the current value of brightness? I assume the values are getting in there even though they have no effect on the screen, but it would be nice to check.
I have now noticed there are several other acpi keys that don't work. Should I add that information here, or write a separate bug report for each one?
(In reply to comment #9) > Just out of curiosity, can you tell me a command to find out the current > value > of brightness? "cat /proc/acpi/video/*/brightness" (In reply to comment #10) > I have now noticed there are several other acpi keys that don't work. Should > I > add that information here, or write a separate bug report for each one? what ACPI keys did you notice?
ping...
Hi. I'm not the original poster but experience similar symptoms and am interested in getting this to work, so please just tell me what you need. laptop: Acer Extensa 5220, there seem to be different versions around kernel 2.6.32.3 x86_64 on Arch Linux, so it's pretty vanilla acpiclient 1.4 So far I can only tell you whether special keys have immediate user-visible effect, I don't know how to see whether they have any effect at all. Special keys: seven special keys on the left -> no effect Fn Keys: Fn numpad - works Fn F1 - nothing, label: ? Fn F2 - nothing, label: cake with a pie cut out? Fn F3 - nothing, label: circle-like with a check mark inside Fn F4 - nothing, label: Z with superscript z Fn F5 - nothing, label: empty rectangle | filled rectangle Fn F6 - seems to turn backlight off Fn F7 - turns touchpad off/on (on with delay of ~1-2 sec.) Fn F8 - nothing visible in alsamixer, label: speaker / speaker emitting sound Fn F11 - numlock, label: Num Fn F12 - nothing, not sure how to test, label: Rol Fn UpArrow - nothing visible in alsamixer, label: louder Fn DownArrow - nothing visible in alsamixer, label: quieter Fn LeftArrow - nothing, label: filled sun Fn RightArrow - nothing, label: empty sun I tested Fn Left-/RightArrow after I read this and can confirm that it works at bios and grub. There are also the Print and Pause keys, not sure whether these are special too. There is: /sys/class/backlight/acpi_video0/ actual_brightness bl_power brightness device/ max_brightness power/ subsystem/ uevent sudo echo 5 > /sys/class/backlight/acpi_video0/brightness bash: /sys/class/backlight/acpi_video0/brightness: Permission denied Please tell me what else you need.
(In reply to comment #13) > There is: > /sys/class/backlight/acpi_video0/ > actual_brightness bl_power brightness device/ > max_brightness power/ subsystem/ uevent > > sudo echo 5 > /sys/class/backlight/acpi_video0/brightness > bash: /sys/class/backlight/acpi_video0/brightness: Permission denied > please run this command as root users and see if the backlight is actually changed after this command.
It changes the backlight as user root but not as normal user using sudo.
Philipp, okay, the ACPI backlight sysfs I/F does work on this laptop, while it's not sure for the laptop of the original bug reporter. so this is a different problem, please file a new bug report. close this bug report because there is no update from the bug reporter since 2009-11-22.