# /proc/acpi/video missing (Kernel 2.6.27)

## Tux12Fun

Hi

I have a Samsung R560 Laptop, and I can't controll Display Backlight brightness because /proc/acpi/video is missing

Any ideas how I can control the backlight of my Laptop

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## pappy_mcfae

Perhaps try a kernel that's marked as stable. Considering that the .27 family is still in release candidate status, I wouldn't use it for anything. try 2.6.26.5 instead. Or you could also click on the link in my sig, and see how I set things up with my seed kernels.

Blessed be!

Pappy

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## Tux12Fun

I need 2.6.27 for my network drivers.

Normaly i wouldn't used it.

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## pappy_mcfae

Then write a bug report to kernel.org so they can figure out what's happening.

Blessed be!

Pappy

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## figueroa

Regarding /proc/acpi/video, there is no CONFIG_ACPI_VIDEO in the the stable x86 2.6.25-gentoo-r7 or r8 either or the noted seed kernels in this thread.  I too am using linux-2.6.27-gentoo-r4 (and -r2 and -r3 before that) needed for the wireless driver which also doesn't have CONFIG_ACPI_VIDEO and I can't control my brightness either.

I have no such problem with this laptop (emachine D620) with Linux Mint or Xubuntu kernels 2.6.24-21.

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## dmpogo

Unless your issue is that you did not enable video part of ACPI (or did not load video module) you can use

/sys/devices/virtual/backlight/acpi_video1/brightness

(or pehaps video0)

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## figueroa

There is no VIDEO part of ACPI.  The CONFIG_ACPI_VIDEO is missing in .config as noted above.

I did find /sys/class/backlight/acer-wmi/brightness that contains the value 9.  It will take a lower, but not a higher, value with echo "5" /sys/class/backlight/acer-wmi/brightness but it doesn't seem to do anything.

acpid is loaded at boot.

acpitool doesn't show anything helpful.

I'm reasonably lost.

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## dmpogo

 *figueroa wrote:*   

> There is no VIDEO part of ACPI.  The CONFIG_ACPI_VIDEO is missing in .config as noted above.
> 
> I did find /sys/class/backlight/acer-wmi/brightness that contains the value 9.  It will take a lower, but not a higher, value with echo "5" /sys/class/backlight/acer-wmi/brightness but it doesn't seem to do anything.
> 
> acpid is loaded at boot.
> ...

 

I hope you do 'echo 5 > /....' with redirection sign ?

Go to /usr/src/linux

run 

make menuconfig

go to Power Management Options -> ACPI Support

What does VIDEO line say ?

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## dmpogo

 *figueroa wrote:*   

> There is no VIDEO part of ACPI.  The CONFIG_ACPI_VIDEO is missing in .config as noted above.
> 
> I did find /sys/class/backlight/acer-wmi/brightness that contains the value 9.  It will take a lower, but not a higher, value with echo "5" /sys/class/backlight/acer-wmi/brightness but it doesn't seem to do anything.
> 
> acpid is loaded at boot.
> ...

 

The fact that you have /sys/class/backlight/acer-wmi/   means it is created not by regular ACPI VIDEO module but by custom

acer-wmi  . Perhaps enabling it forced disable several ACPI choices.

I checked it on my kernel, and enabling ACER-WMI Extras did not disable ACPI VIDEO.

However, perhaps you are better off using ACER-WMI

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## figueroa

Even disabling the ACER-WMI under drivers, the ACPI section still reads:

 *Quote:*   

> 
> 
> --- ACPI (Advanced Configuration and Power Interface) Support  
> 
> [*]   Deprecated /proc/acpi files  
> ...

 

No VIDEO option.  This is from 2.6.27-r4, but the video option is also missing in my .config in all of my 2.6.25 kernel sources.

Thanks for trying to help.

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## dmpogo

Wow,

so echoing number into brightness, did it change the value (cat brightness), even if it did nothing to the screen ?

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## dmpogo

 *figueroa wrote:*   

> Even disabling the ACER-WMI under drivers, the ACPI section still reads:
> 
>  *Quote:*   
> 
> --- ACPI (Advanced Configuration and Power Interface) Support  
> ...

 

can you move your .config to the safe location, and try without it, will the option appear ? I also use the same kernel you do, BTW

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## figueroa

Good idea - or so it seems.

I deleted all the .config(s) and ran "make clean" then "make menuconfig."

No difference.  Since you are running the same kernel, I assume that you also don't have CONFIG_ACPI_VIDEO.

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## dmpogo

 *figueroa wrote:*   

> Good idea - or so it seems.
> 
> I deleted all the .config(s) and ran "make clean" then "make menuconfig."
> 
> No difference.  Since you are running the same kernel, I assume that you also don't have CONFIG_ACPI_VIDEO.

 

I do have ACPI VIDEO

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## figueroa

Are you running vanilla-sources?

I'm running gentoo-sources ~x86.

***ADDED***

Not that it matters.  I've looked all through Pappy's seed kernels and don't find CONFIG_ACPI_VIDEO in any of them, gentoo or vanilla.  My running a 2.6.24 kernel on my desktop and none there either.  Still, there is an active dialog about this module/driver on the web where I saw it indicated that this driver has been around since 2.6.12 and is still in the developing 2.6.27 series.

On a more positive note, I DO find this in my Debian kernels (Linux Mint, Xubuntu, etc).  Sigh.

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## dmpogo

 *figueroa wrote:*   

> Are you running vanilla-sources?
> 
> I'm running gentoo-sources ~x86.
> 
> ***ADDED***
> ...

 

I run gentoo-sources-2.6.27-r4, as well as before I run gentoo-sources-2.6.27-r2 and  gentoo-sources-2.6.25-r7.

ACPI_VIDEO is there and always has been.

```

CONFIG_ACPI_VIDEO=y

# CONFIG_THINKPAD_ACPI_VIDEO is not set

```

Here is what make system has for it, in linux/drivers/acpi/Kconfig

```

config ACPI_VIDEO

   tristate "Video"

   depends on X86 && BACKLIGHT_CLASS_DEVICE && VIDEO_OUTPUT_CONTROL

   depends on INPUT

   select THERMAL86, 

```

Thus, in requires X86, BACKLIGHT_CLASS_DEVICE and VIDEO_OUTPUT_CONTROL   enabled

so go to

```

Device Drivers -> Graphics  Support

```

and enable 

```

LowLevel video output switch controls

```

and 

```

Backlight and LCD device support.

```

Then go inside and enable

```

LowLevel LCD Controls

Platform LCD Controls

```

and, critically

```

LowLevel Backlight Controls

```

The go back in the menu and see if ACPI VIDEO appeared

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## figueroa

Bless your li'l heart.  I followed your instructions, and voila, the item for CONFIG_ACPI_VIDEO miraculously appeared.  I recompiled the kernel and now have Fn key control over brightness. (Fn/left arrow & Fn/right arrow).

Thank you!

This should have definitely not been that hard to get to.  Any kernel developers reading?

Couriously, raising or lowering brightness results in the following messages in dmesg:

 *Quote:*   

> 
> 
> atkbd.c: Unknown key pressed (translated set 2, code 0xf8 on isa0060/serio0).
> 
> atkbd.c: Use 'setkeycodes e078 <keycode>' to make it known.
> ...

 

Use setkeycode where?  This is humbling.

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## dmpogo

 *figueroa wrote:*   

> Bless your li'l heart.  I followed your instructions, and voila, the item for CONFIG_ACPI_VIDEO miraculously appeared.  I recompiled the kernel and now have Fn key control over brightness. (Fn/left arrow & Fn/right arrow).
> 
> Thank you!
> 
> This should have definitely not been that hard to get to.  Any kernel developers reading?
> ...

 

well,  if brightness is changing, ignore (I don't really know atkbd)

But, if you are interested,  we can investigate a bit.   Brightness keys usually generate ACPI events,   but it looks like in your case they

do generate regular keycodes as well (on my machine they do not, here different hardware may be different).

You do have acpid installed, do you ?   If not instal acpid and also 'xev' package.

1) Now, you get 'acpi_listen' command.  Run it in terminal and press your Fn-arrow combination.  Do you see ACPI events reported ?

2) Run 'xev'  in the terminal.   Put your cursor in the square box that appears and press again Fn-arrows. Do you see keycodes reported in the

terminal ?

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## overkll

I think I told you in another post that setting keycodes/hotkeys is tricky.  Looks like you'll have to define a few custom ones.  I had to as well for my new laptop.  I got the instructions from HAL quirks at freedesktop.org.

Enjoy!

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## dmpogo

 *overkll wrote:*   

> I think I told you in another post that setting keycodes/hotkeys is tricky.  Looks like you'll have to define a few custom ones.  I had to as well for my new laptop.  I got the instructions from HAL quirks at freedesktop.org.
> 
> Enjoy!

 

Nothing tricky, especially if one does not use HAL  :Smile: 

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## figueroa

dmpogo,

I do have acpid running (loads at boot level).  Also hald.

Following instructions ...

acpid_listen reveals (comment added):

 *Quote:*   

> 
> 
> video LCD 00000087 00000000 # bright down - Fn/left
> 
> video LCD 00000086 00000000 # bright up - Fn/right
> ...

 

I then emerged xev.  Results:

 *Quote:*   

> 
> 
> KeyPress event, serial 31, synthetic NO, window 0x2800001,
> 
>     root 0x89, subw 0x0, time 3683837131, (-195,2, root:(371,362),
> ...

 

(The smilies are an unintended surprise.)

The first set is Fn/left and the second set is Fn/right.  It would appear the keycodes are 123 and 212.

I am appreciating the tutoring.

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## dmpogo

 *figueroa wrote:*   

> dmpogo,
> 
> I do have acpid running (loads at boot level).  Also hald.
> 
> Following instructions ...
> ...

 

Yep, so in addition to standard ACPI events keycodes are also generated but are not mapped to any Symbols (which is a job of xkb subsystem),

and that is what atkbd was complaining about. This gives possibility for some desktop applications to modify brightness without going through 

explicit ACPI signal handling so there are two paths to choose from. If it works, you can ignore the second path for now.

I checked and found that my brighness buttons also generate keycodes as well as ACPI events.

I have Fn-Home as brightness up and Fn-End as down and it generates 212 on UP but 101 on Down   :Smile: 

So I learnt something new myself !

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## dmpogo

If we are done with this topic, it is best to edit subject marking it solved  :Smile: 

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## tbart

well... wait!

I still have a problem with my lenovo thinkpad t61p..

up until 2.6.24-r4 I had *NO*

```
Lowlevel video output switch controls

Backlight & LCD device support
```

config options set in my kernel, and thinkpad_acpi said

```
thinkpad_acpi: standard ACPI backlight interface available, not loading native one...
```

everything worked as expected, no acpid or other event handling in userspace necessary...

Now I updated to 2.6.27-r7. 

```
-*- Backlight & LCD device support

      {*}   Lowlevel Backlight controls
```

now get selected by thinkpad_acpi and I cannot de-select them. brightness buttons now do *NOT* work anymore.

I even tried selecting all the options mentioned above by dmpogo to no avail...

I'd like to have a solution without a userspace app, as it has been working perfectly without this.

dmpogo, your keycode (at least the one for brightness up - interestingly, i do not get one for brightness down) is the same as I have, so I guess you might also have a thinkpad..

Could you post your relevant .config parts if you have a working solution without a userspace app?

or can anyone else help?

thanks in advance!

th

----------

## dmpogo

 *tbart wrote:*   

> well... wait!
> 
> I still have a problem with my lenovo thinkpad t61p..
> 
> up until 2.6.24-r4 I had *NO*
> ...

 

I do have a thinkpad (X300), however I use acpid solution.  As I understand video support in thinkpad_acpi is considered broken, and system always 3chooses standard acpi video handling over it.

----------

## tbart

update!

I don't know what I've done wrong but I just went over my config again and now it works.

basically, it seems, you only need

CONFIG_VIDEO_OUTPUT_CONTROL (as it is necessary for:)

CONFIG_ACPI_VIDEO

you do not need

CONFIG_THINKPAD_ACPI_VIDEO

[url]http://www.nabble.com/T61-Brightness-keys-with-2.6.26-not-working-(NVIDIA)-td18577619.html[/url] has a discussion about this.

no userspace app necessary now. Maybe that helps others as well (I personally dislike running daemons for things that can be done in hardware as well...)

 *Quote:*   

> I do have a thinkpad (X300), however I use acpid solution. As I understand video support in thinkpad_acpi is considered broken, and system always 3chooses standard acpi video handling over it.

 

well, yes, the kernel config's help for thinkpad acpi's video option does not sound too promising ;->

but the brightness control part works flawlessly.

```
/usr/src/linux/Documentation/laptops/thinkpad-acpi.txt
```

 is a good doc about all of this. It states that the backliight handling is turned of by thinkpad_acpi if it detects standard ACPI video handling is possible (this is my case)

However, even if your thinkpad can do ACPI video controls, you can force thinkpad_acpi (see the .txt file) to use its own routines for doing that. this also works with my t61p.

the only "problem" that remains (well, i currently do not use much of my buttons) is that thinkpad_acpi does not work at all at the moment, as my kernel ony says:

```
thinkpad_acpi: Unknown symbol backlight_device_unregister

thinkpad_acpi: Unknown symbol backlight_device_register
```

but i'll get that fixed as well somehow

----------

## tbart

well I have to correct this.

it works as long as i do not load thinkpad_acpi (or it does not get loaded because of missing symbols)

i could not even solve this in userspace, as the buttons do not generate acpi or input events...

And now we're back to the topic's initial question:

I don't have /proc/acpi/video, nor /sys/devices/virtual/backlight/acpi_video1/brightness, nor /sys/class/backlight/* ...

seems the ACPI video part does not really work.

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## dmpogo

 *tbart wrote:*   

> well I have to correct this.
> 
> it works as long as i do not load thinkpad_acpi (or it does not get loaded because of missing symbols)
> 
> i could not even solve this in userspace, as the buttons do not generate acpi or input events...
> ...

 

well, for me thinkpad_acpi was needed to have Fn-F?? keys to work.   Otherwise, I am already confused what at the end you do or do not have compiled in the kernel.

userland tools through acpid work just fine, BTW.   I even have an OSD  slider showing me the brightness level

----------

## tbart

yes, you definitely need thinkpad_acpi to make Fn-Fx keys (and music control and volume up/down/mute) work. but (at least that's the case with my t61p) for brightness, you do not need any special handling, not in userspace and not even by the kernel. brightness up/down works in the BIOS or before even booting linux as well, so this can be done in pure hardware. and that's what i want it to work like again...

my current config is at http://www.rockbrew.com/var/config-2.6.27-gentoo-r7

having an OSD for the levels may be a fine thing (although personally I do not want it) if only you have events produced by the Fn combinations. I'd not even need that, because it could be any combination with regular keys as well, I would not mind too much. but neither do i have acpi or input key events nor do i have any interface to control the brightness (not in /sys and not in /proc)

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## dmpogo

 *tbart wrote:*   

> yes, you definitely need thinkpad_acpi to make Fn-Fx keys (and music control and volume up/down/mute) work.

 

Interesting, on my thinkpand I do not need thinkpad_acpi for music control and volume up/down/mute.

Mute is run by BIOS,   while the rest generate standard keycodes, and not acpi events.

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## tbart

big sorry, I'm really ashamed of this...

copied over the new kernel every time, but the grub.conf file referenced a slightly different name. my fault.

now everything's working as it should... entries in /sys/class/backlight are there and fully functional, thinkpad_acpi part as well.

no userspace apps needed. i'm happy again ;->

Thanks a lot for your help!

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## dmpogo

 *tbart wrote:*   

> big sorry, I'm really ashamed of this...
> 
> copied over the new kernel every time, but the grub.conf file referenced a slightly different name. my fault.
> 
> now everything's working as it should... entries in /sys/class/backlight are there and fully functional, thinkpad_acpi part as well.
> ...

 

it happens   :Very Happy: 

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