Bug 14548 - Brightness controls on Acer emachine D725 to not work
Summary: Brightness controls on Acer emachine D725 to not work
Status: CLOSED INSUFFICIENT_DATA
Alias: None
Product: ACPI
Classification: Unclassified
Component: BIOS (show other bugs)
Hardware: All Linux
: P1 high
Assignee: acpi_bios
URL:
Keywords:
Depends on:
Blocks:
 
Reported: 2009-11-05 19:13 UTC by Ian Smith
Modified: 2010-01-13 06:55 UTC (History)
3 users (show)

See Also:
Kernel Version: 2.6.31.5-0.1-desktop x86_64
Subsystem:
Regression: No
Bisected commit-id:


Attachments
dmidecode output from this machine (20.96 KB, text/plain)
2009-11-05 19:15 UTC, Ian Smith
Details
acpidump emachine D725 (204.94 KB, text/plain)
2009-11-06 08:57 UTC, Ian Smith
Details
LSPCI: emachine D725 (1.92 KB, text/plain)
2009-11-06 08:58 UTC, Ian Smith
Details
Error messages from the acpidump (196 bytes, text/plain)
2009-11-06 09:00 UTC, Ian Smith
Details

Description Ian Smith 2009-11-05 19:13:53 UTC
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"
Comment 1 Ian Smith 2009-11-05 19:15:45 UTC
Created attachment 23666 [details]
dmidecode output from this machine
Comment 2 ykzhao 2009-11-06 05:50:31 UTC
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
Comment 3 Ian Smith 2009-11-06 08:57:07 UTC
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"
Comment 4 Ian Smith 2009-11-06 08:58:51 UTC
Created attachment 23676 [details]
LSPCI: emachine D725
Comment 5 Ian Smith 2009-11-06 09:00:44 UTC
Created attachment 23677 [details]
Error messages from the acpidump
Comment 6 Zhang Rui 2009-11-09 08:57:51 UTC
it seems that ACPI backlight control fails to work for your laptop.
what if you boot with "acpi_backlight=vendor"?
Comment 7 Ian Smith 2009-11-09 18:24:26 UTC
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.
Comment 8 Zhang Rui 2009-11-17 01:28:41 UTC
(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. :)
Comment 9 Ian Smith 2009-11-22 12:12:18 UTC
(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.
Comment 10 Ian Smith 2009-11-22 14:23:18 UTC
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?
Comment 11 Zhang Rui 2009-12-09 05:40:13 UTC
(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?
Comment 12 Zhang Rui 2009-12-22 03:45:34 UTC
ping...
Comment 13 Philipp Überbacher 2010-01-10 10:10:49 UTC
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.
Comment 14 Zhang Rui 2010-01-11 01:20:33 UTC
(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.
Comment 15 Philipp Überbacher 2010-01-11 11:08:52 UTC
It changes the backlight as user root but not as normal user using sudo.
Comment 16 Zhang Rui 2010-01-13 06:55:07 UTC
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.

Note You need to log in before you can comment on or make changes to this bug.