Bug 27172 - brightness levels are not right
Summary: brightness levels are not right
Status: CLOSED INSUFFICIENT_DATA
Alias: None
Product: ACPI
Classification: Unclassified
Component: Power-Video (show other bugs)
Hardware: All Linux
: P1 normal
Assignee: acpi_power-video
URL:
Keywords:
Depends on:
Blocks:
 
Reported: 2011-01-20 14:10 UTC by 00oo00
Modified: 2012-01-18 02:37 UTC (History)
4 users (show)

See Also:
Kernel Version: Linux 2.6.35-24-generic
Subsystem:
Regression: No
Bisected commit-id:


Attachments
lsmod report (106 bytes, text/plain)
2011-01-20 14:10 UTC, 00oo00
Details
acpidumps (11.43 KB, application/x-zip-compressed)
2011-02-10 14:27 UTC, 00oo00
Details

Description 00oo00 2011-01-20 14:10:56 UTC
Created attachment 44492 [details]
lsmod report

I have a kinda old laptop. Just installed Ubuntu 10.10 Mavericks but I come across some problems. Most inportantly is the brightness control problem. My laptop has 8 levels adjustment settings. But only 4 levels can be adjust when I press Fn+F7 and FN+F8 to change to the maximum or minimum. I think this is a bug and wanna solve it, so I reported here. I used this command below to check the brightness levels info in the /proc/acpi/video/GFX0/DD03/brightness.
cat '/proc/acpi/video/GFX0/DD03/brightness
It returns these values below.
levels: 13 25 38 50 63 75 88 100
current: 63
And I checked the /proc/acpi/video/GFX0/DD03/EDID, it's empty. Is this normal or Ubuntu hasn't recognized my laptop LCD correctly?

I did dmesg|tail -5 command and it returns this below.
[ 2025.850319] EXT4-fs (sda4): re-mounted. Opts: errors=remount-ro,commit=0
[ 2772.758260] ACPI: Please implement acpi_video_bus_ROM_seq_show
[ 2772.937960] ACPI: Please implement acpi_video_bus_ROM_seq_show
[ 2775.236182] ACPI: Please implement acpi_video_bus_ROM_seq_show
[ 2785.830043] ACPI: Please implement acpi_video_bus_ROM_seq_show

Ismod attached.
Please help me make this amazing OS run flawlessly on my laptop. Thanks in advance.
Comment 1 Rafael J. Wysocki 2011-01-20 20:35:29 UTC
The kernel in your distro is not very fresh, so to speak.

Please report this problem to Ubuntu first.
Comment 2 00oo00 2011-01-21 07:11:06 UTC
(In reply to comment #1)
> The kernel in your distro is not very fresh, so to speak.
> 
> Please report this problem to Ubuntu first.

I did. My kernel has been upgraded to 2.6.35-24-generic. The issue remains.
Comment 3 ykzhao 2011-01-25 01:07:28 UTC
Will you please attach the output of acpidump on your box?

Will you please try the /sys/class/backlight/*/brightness and see whether the brightness level can be adjusted? 

Thanks.
Comment 4 00oo00 2011-01-25 08:27:24 UTC
(In reply to comment #3)
> Will you please attach the output of acpidump on your box?
> 
> Will you please try the /sys/class/backlight/*/brightness and see whether the
> brightness level can be adjusted? 
> 
> Thanks.

Well Itried run this command but what it gives back this below.
chan:~# /sys/class/backlight/*/brightness
bash: /sys/class/backlight/acpi_video0/brightness: Permission denied
Comment 5 ykzhao 2011-02-01 00:47:19 UTC
Does there exist the interface of /sys/class/backlight/*/brightness on your box? 

It will be great that you can attach the output of acpidump on your box.

Thanks.
Comment 6 Zhang Rui 2011-02-09 02:34:59 UTC
ping
Comment 7 00oo00 2011-02-10 14:27:41 UTC
Created attachment 47132 [details]
acpidumps

acpi dumps that might be helpful for this issue
Comment 8 00oo00 2011-02-10 14:30:34 UTC
(In reply to comment #5)
> Does there exist the interface of /sys/class/backlight/*/brightness on your
> box? 
> It will be great that you can attach the output of acpidump on your box.
> Thanks.
Hi, ykzhao. Thanks for replying and happy new year. Below is what responds to what u told me to run in terminal.
bash: /sys/class/backlight/acpi_video0/brightness: Permission denied
It appears system have denied to output the info about this. 
Regards 
alex
Comment 9 00oo00 2011-02-10 14:31:47 UTC
(In reply to comment #6)
> ping

I have been busy lately. happy new year, dude.
Comment 10 Zhang Rui 2012-01-18 02:37:15 UTC
Hi, Happy New Year 2012!. :)

Bug closed as there is no response for more than a year.
Please feel free to reopen it if the problem still exists in the latest upstream kernel.

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