Bug 13955

Created attachment 22672 [details]
debug patch

please apply this debug patch on top.

This laptop has buggy _BQC implemented.
From the dmesg, we can see the _BQC returns 2351 after boot, which is surely an invalid value.

I think we should have brightness support with this debug patch.
does the brightness sysfs I/F and hotkeys work this time?
if not, please attach the dmesg output after poking the backlight sysfs I/F.

Created attachment 22673 [details]
dmesg output with 5715 patch when brightness work (unfortunately it isn't working at every boot)

i will try the patch (i did a full kernel compilation for the two other patchs)
the fun is, i power on my computer at work this morning and the brightness work ....

just in case here is a second dmesg

but i will compile the driver with path in comment 1,
i will give you feedback ASAP and hope it will work every time ^^

ps : after this battle, i'm going to bother the KMS team for making brightness work there too

Created attachment 22674 [details]
the new dmesg with patch given in comment 1 of this report

i applied the patch
only compile the video.ko driver the way you told me : 
make modules M=drivers/acpi/

after this, i did a 
cp drivers/acpi/video.ko /lib/modules/2.6.31-rc5video/kernel/drivers/acpi/video.ko

(insmod is not working, because driver is in use :( )

i reboot
and the brightness is working

unfortunatly, i use my computer to work right now, so i can not reboot or power down often

i will do some more tests after work

now i also have a acpi_video0 in /sys/class/backlight

and the result of cat /proc/acpi/video/*/*/brightness
is now :
<not supported>
<not supported>
levels:  10 20 30 40 50 60 70 80 90 100
current: 100
<not supported>
<not supported>

doing echo 3 > /sys/class/backlight/acpi_video0/brightness
now work too

as well as xbacklight and gnome backlight applet ^^


REALLY REALLY THANK YOU !!! this bug was disturbing me a lot

i did an other test
i shut down the computer
plug out the power
wait a little
power on
test brightness => work without a problem
plug power in => work without a problem ^^
check dmesg to see if there is some kind of ACPI error/warning => nothing :)

once again thank you Rui !

can you put the patches in next kernel ?

good news. :) 
As I said in comment #1, the bug of your laptop is that _BQC returns an uninitialized value for the first time.
This explains why the backlight works sometimes because it may return a value less than 10 occasionally, which is actually supported.
I'll generate a patch to workaround this issue, but it needs a couple of days to hit upstream because we have a lot of changes in ACPI video driver recently. :)

Created attachment 22675 [details]
patch for upstream,  which is based on top of Dmitry's changes

Alain,
In order to test this patch, you need to apply the patches at:
http://patchwork.kernel.org/patch/40097/
http://patchwork.kernel.org/patch/40098/
http://patchwork.kernel.org/patch/40099/
http://patchwork.kernel.org/patch/40100/
and
http://patchwork.kernel.org/patch/40348/
first. :)

ok i will give a try
should i begin with the unpatched video.c driver, or should i apply these patches directly on the current version (with 5715 patch, comment1 patch, debug patch)

just on top of the 5715 patch, which will hit upstream soon. :)

ok i will give you some feedback ASAP

once again thanks for your help !

it work :)

but there is a little bug on my computer 

it may be a keypress or key release problem, i don't think it came from the patches... but i didn't notice it before, so i'm not sure...

but even with this kind of bug, its a lot better, than no brightness change possibility

i have brightness at 100%
i press once the decrease brightness key
and on screen i see that the brightness decrease twice


alain@ubuntu:/proc/acpi/video/OVGA/DD03$ cat brightness 
levels:  10 20 30 40 50 60 70 80 90 100
current: 100

I press decrease once 

alain@ubuntu:/proc/acpi/video/OVGA/DD03$ cat brightness 
levels:  10 20 30 40 50 60 70 80 90 100
current: 70

but like i said, this is not as disturbing as having no way to change the brightness level

please attach the output of "grep . /sys/firmware/acpi/interrupts/*" both before and after pressing the hotkey.

Created attachment 22684 [details]
the result before keypress

ok here are the results

Created attachment 22685 [details]
result after one keypress on brightness down key

re-opening, since the patch in comment #7 doesn't apply to upstream,
and applies only on top of patches that no longer apply to upstream.
(ie. needs re-fresh)

Same problem with kernels 2.6.30-2.6.31 on Acer Aspire 5530. On kernel 2.6.29 brightness is controllable, but also there are some problems : during boot it decreases to the lowest level (10); when i try to increase it, sometimes it's resisting to increasing :); when i'm decreasing it, it decreases by 30 (not 10).

Created attachment 22918 [details]
patch based on upstream kernel

Created attachment 22919 [details]
patch based on upstream kernel v2

commit 90c53ca426cb93d15eefea79dcf6bd15ad3ffeb4
Author: Zhang Rui <rui.zhang@intel.com>
Date:   Mon Aug 31 12:39:54 2009 -0400

    ACPI video: work-around BIOS AML bug in _BQC

applied to acpi-test tree

hi, do i need to apply other patchs to make it work, or is the patch in comment #19 working alone ?

well, i'll try this patch on ubuntu kernel 2.6.31-10 and give feedback ASAP

Well i applied the patch in comment #19 on the last ubuntu kernel, and brightness did not work... still have ACPI: Failed to switch the brightness

can you redo the test and attach the dmesg output as you did in comment #0?

Created attachment 23146 [details]
dmesg on ubuntu 2.6.31-10.35

I applied the debug patch, and the patch in comment #19, here is the dmesg

FYI
commit 90c53ca426cb93d15eefea79dcf6bd15ad3ffeb4
Author: Zhang Rui <rui.zhang@intel.com>
Date:   Mon Aug 31 12:39:54 2009 -0400

    ACPI video: work-around BIOS AML bug in _BQC


shipped in Linux-2.6.31-git-14

Created attachment 23195 [details]
disable _BQC if it returns an invalid value

please try this patch.

thanks
it's not working 100% but it's working, let me explain

on X without KMS when i press the brightness keys it change the brightness (but gnome did not show the progress bar of the brightness level)

on console mode, the brightness is not changing and i still receive 
ACPI: Failed to switch the brightness

the gnome brightness applet is not working, maybe because of

cat /proc/acpi/video/*/*/brightness
<not supported>
<not supported>
<not supported>
<not supported>
<not supported>

alain@portable-al1:/sys/class/backlight$ ls
alain@portable-al1:/sys/class/backlight$ 


but like i said i can at least change the brightness.

i forgot to say, that the ACPI: Failed to switch the brightness always come, even after successfully changing brightness level

i don't know if this change anything, but i just apply the patch given on comment #26, nothing else....
maybe i needed some other patch to made it work 100%

Any news? Any patch to try? I have the same laptop and this bug is very annoying.

Created attachment 23314 [details]
patch: disable _BQC once it returns an invalid value

please try this patch.
and attach the dmesg output after you pressing the hotkey for several times.

(In reply to comment #27)
> 
> cat /proc/acpi/video/*/*/brightness
> <not supported>
> <not supported>
> <not supported>
> <not supported>
> <not supported>
>
this is weird, the acpi video backlight interface should be working.

please apply the debug patch attached below on top of the patch in comment #30,
and attach the dmesg output.

Created attachment 23315 [details]
debug patch

ping...

close this bug as there is no response from the bug reporter for more 2 months.
please reopen it if you can provide the info request in comment #31.

sorry i was in hollidays on october and i didn't saw the mail received from bugzilla until now

on pre alpha (i know ... i'm silly to use unstable version ^^) ubuntu lucid lynx (kernel 2.6.32) here are the outputs

cat /proc/acpi/video/*/*/brightness
<not supported>
<not supported>
levels:  10 20 30 40 50 60 70 80 90 100
current: 100
<not supported>
<not supported>

root@portable-al1:/sys/class/backlight# ls
acpi_video0

and video brightness is working well (it does so on karmic final too)

once again sorry for not answering you faster

so you mean the backlight works well even without the patch from comment #30 and any other patch?

well actually i have official ubuntu kernel without needing to patch it...
maybe they apply the given patch...

If there is a problem with the upstream kernel.org kernel,
please re-open this bug.