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#1 2013-06-07 05:46:53

HalosGhost
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From: Twin Cities, MN
Registered: 2012-06-22
Posts: 1,915
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[SOLVED] nVidia GeForce GT 750M backlight control

Using xf86-video-nouveau and the open-source drivers, there is no controllable backlight interface in /sys/class/backlight (just acpi_video0 which changes nothing when I manipulate it). I tried using the nvidiabl driver, but apparently it doesn't support this GPU.

So, I tried switching to the proprietary drivers, but there was still no usable interface in /sys/class/backlight.

Anyone have any thoughts on what I could do to actually be able to change the brightness of my screen? tongue

All the best,

-HG

Last edited by HalosGhost (2013-07-08 17:35:51)

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#2 2013-06-07 06:47:36

T.J.S.
Member
Registered: 2012-08-14
Posts: 83

Re: [SOLVED] nVidia GeForce GT 750M backlight control

Try setting the kernel parameter "acpi_osi=<space(s)>" in Grub and then change the brightness with the Fn keys.
(source: https://bbs.archlinux.org/viewtopic.php … 8#p1203448)

It worked for me with NVIDIA's proprietary drivers, even though /sys/class/backlight was empty.

Last edited by T.J.S. (2013-06-07 06:49:32)

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#3 2013-06-07 13:56:39

HalosGhost
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From: Twin Cities, MN
Registered: 2012-06-22
Posts: 1,915
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Re: [SOLVED] nVidia GeForce GT 750M backlight control

Alright. Well, this is my first UEFI install (and I'm using EFISTUB, not GRUB), but I imagine that may work. I'll give it a shot and report back.

All the best,

-HG

Well, as an option passed to gummiboot, this solution did not work. I tried using 'acpi_osi="!Windows 2012"' as some recommended and 'acpi_osi="Linux"' as others did, but neither yielded functional results. Any other ideas?

Last edited by HalosGhost (2013-06-07 14:27:49)

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#4 2013-06-07 15:01:47

T.J.S.
Member
Registered: 2012-08-14
Posts: 83

Re: [SOLVED] nVidia GeForce GT 750M backlight control

Hm, I forgot to mention that I also created a xorg config file for nvidia, just like this:
https://bbs.archlinux.org/viewtopic.php … 8#p1248838

You might wanna tinker with "acpi_backlight" parameter in conjunction with "acpi_osi", see if it gives you anything. (either with the FN keys or /sys/class/...etc)

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#5 2013-06-07 20:49:18

HalosGhost
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From: Twin Cities, MN
Registered: 2012-06-22
Posts: 1,915
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Re: [SOLVED] nVidia GeForce GT 750M backlight control

Well, I've switched back to nouveau (as I've had more success with it for other issues; but I'll give this a try with the proprietary ones in a while.

All the best,

-HG

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#6 2013-06-23 05:33:50

HalosGhost
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From: Twin Cities, MN
Registered: 2012-06-22
Posts: 1,915
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Re: [SOLVED] nVidia GeForce GT 750M backlight control

Okay, progress update. With the following options:

acpi_osi="Linux" acpi_backlight="vendor"

I now have a wonderful "ideapad" folder in /sys/class/backlight. Unfortunately, changing the values of the brightness file has no effect on the actual brightness of the screen (though the actual_brightness file does recognize the change). The Function keys still have no effect. Any other recommendations?

All the best,

-HG

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#7 2013-07-08 17:35:24

HalosGhost
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From: Twin Cities, MN
Registered: 2012-06-22
Posts: 1,915
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Re: [SOLVED] nVidia GeForce GT 750M backlight control

Victory! I finally have control over my backlight. As it turns out, adding support for this GPU to the nvidiabl driver is trivial. I used the following PKGBUILD to do the job (it is just a modified version of the nvidiabl PKGBUILD in the AUR):

_name=nvidiabl
pkgname="${_name}-git"
pkgver=69.gb3b9270
pkgrel=1
pkgdesc="Driver to adjust display backlight on modern mobile NVidia graphics adapters."
arch=('x86_64' 'i686')
url="https://github.com/guillaumezin/nvidiabl"
license=('GPL')
makedepends=('linux-headers')
optdepends=('nvidiablctl: adjust backlight easily')
conflicts=('nvidia-bl')
install="${_name}.install"
source=("${_name}::git://github.com/guillaumezin/nvidiabl")
sha256sums=('SKIP')

MODPATH="${pkgdir}/usr/lib/modules/$(uname -r)/kernel/drivers/video/backlight/"

pkgver() {
   cd "${_name}"
   echo "$(git rev-list --count HEAD).$(git describe --always|cut -d "-" -f3)"
}

prepare() {
   cd "${_name}"
   echo 'NVIDIABL_DECLARE_LAPTOP_MODEL("LENOVO", "20193", PCI_ANY_ID, NVIDIABL_SC_AUTO, NVIDIABL_AUTO, NVIDIABL_AUTO, 0x1FFFF),' >> nvidiabl-laptops.h
   echo 'NVIDIABL_DECLARE_GPU_MODEL(0x0fe4, nv5x_driver_data),' >> nvidiabl-gpu.h
}

build() {
   cd "${_name}"
   make
}

package() {
   cd "${_name}"
   install -Dm644 -c nvidiabl.ko "${pkgdir}/$MODPATH/nvidiabl.ko"
}

I kept the same .install file from the AUR package, and voila! I am now able to modify the brightness file located in /sys/class/backlight/nv_backlight and the actual screen brightness changes as well!

All the best,

-HG

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#8 2013-08-26 20:52:06

zacariaz
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Registered: 2012-01-18
Posts: 499
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Re: [SOLVED] nVidia GeForce GT 750M backlight control

Would the above PKGBUILD work for gt 650m? (lenovo ideapad y500 btw)

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#9 2013-08-26 22:23:14

HalosGhost
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From: Twin Cities, MN
Registered: 2012-06-22
Posts: 1,915
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Re: [SOLVED] nVidia GeForce GT 750M backlight control

zacariaz wrote:

Would the above PKGBUILD work for gt 650m? (lenovo ideapad y500 btw)

The computer I use this for is actually a Lenovo IdeaPad Y500, but my card is a GT750M (as the OP mentions), so it might not work as-is but it shouldn't be much different. I'd recommend you open a new thread and reference this one if you can't figure it out.

All the best,

-HG

Last edited by HalosGhost (2013-08-26 22:33:20)

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#10 2013-08-27 08:15:24

zacariaz
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Registered: 2012-01-18
Posts: 499
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Re: [SOLVED] nVidia GeForce GT 750M backlight control

HalosGhost wrote:
zacariaz wrote:

Would the above PKGBUILD work for gt 650m? (lenovo ideapad y500 btw)

The computer I use this for is actually a Lenovo IdeaPad Y500, but my card is a GT750M (as the OP mentions), so it might not work as-is but it shouldn't be much different. I'd recommend you open a new thread and reference this one if you can't figure it out.

All the best,

-HG

I suppose what I meant to say, is how did you find the solution?

If I understand the PKGBUILD correctly, the only think I should need to change is:

echo 'NVIDIABL_DECLARE_GPU_MODEL(0x0fe4, nv5x_driver_data),' >> nvidiabl-gpu.h

Hoever, I haven't got a clue where you got the value "0x0fe4".


Thanks for the comeback and best regards.

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#11 2013-08-27 13:32:09

HalosGhost
Forum Moderator
From: Twin Cities, MN
Registered: 2012-06-22
Posts: 1,915
Website

Re: [SOLVED] nVidia GeForce GT 750M backlight control

zacariaz wrote:

I suppose what I meant to say, is how did you find the solution?

If I understand the PKGBUILD correctly, the only think I should need to change is:

echo 'NVIDIABL_DECLARE_GPU_MODEL(0x0fe4, nv5x_driver_data),' >> nvidiabl-gpu.h

Hoever, I haven't got a clue where you got the value "0x0fe4".


Thanks for the comeback and best regards.

Ahh, I can help you with that. I probably should have pointed to this information sooner, so I'm sorry I didn't. I found this solution by applying the information in this post. It may help you derive what you need.

All the best,

-HG

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#12 2013-08-27 13:35:44

zacariaz
Member
Registered: 2012-01-18
Posts: 499
Website

Re: [SOLVED] nVidia GeForce GT 750M backlight control

HalosGhost wrote:
zacariaz wrote:

I suppose what I meant to say, is how did you find the solution?

If I understand the PKGBUILD correctly, the only think I should need to change is:

echo 'NVIDIABL_DECLARE_GPU_MODEL(0x0fe4, nv5x_driver_data),' >> nvidiabl-gpu.h

Hoever, I haven't got a clue where you got the value "0x0fe4".


Thanks for the comeback and best regards.

Ahh, I can help you with that. I probably should have pointed to this information sooner, so I'm sorry I didn't. I found this solution by applying the information in this post. It may help you derive what you need.

All the best,

-HG

I'll check it out. thanks.

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#13 2013-08-27 13:51:42

zacariaz
Member
Registered: 2012-01-18
Posts: 499
Website

Re: [SOLVED] nVidia GeForce GT 750M backlight control

Would you maybe be so kind as to provide the output of:

lspci -nn |grep VGA

Simply a percussion to ensure I've got the right information.


Thanks.

edit:
never mind that, I figured it out.

I also figured out that whatever the problem is, this ain't the solution.

In short, the max brightness is set way to low, and I've so far been unable to change it.

edit2.

My bad wink

Had to remove the old nvidiabl first obviously.

For people wanting to use this solution for gt 650m, simply change 0x0fe4 to 0x0fd1 and remember to remove the old nvidiabl, if installed wink

Last edited by zacariaz (2013-08-27 14:01:37)

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