And what is model of your netbook?

Hi, @ntalaec,
The only similar thing for DOS, that I know, is DIMMER.COM by Douglas Boling and Jeff Prosise. You can download it from here or here.

theelf wrote on 2026-07-19, 14:22:

And what is model of your netbook?

It's a Sony VPCW11S1E

aVd wrote on 2026-07-19, 19:21:

Hi, @ntalaec,
The only similar thing for DOS, that I know, is DIMMER.COM by Douglas Boling and Jeff Prosise. You can download it from here or here.

Thanks, but it does not work in this computer. The computer hangs when I try to load the application.

There is an utility for DOS for an industrial component which could do the job, but I can't find a download link:
PowerStation Contrast/Brightness Utility

I have also found an utility which allows gamma change but no brightness:
https://www.sac.sk/download/utiltext/brght092.zip

There is also a port of SVGATextMode for DOS that can change frequencies, gamma and text modes but again no brightness:
https://www.ibiblio.org/pub/micro/pc-stuff/fr … 9_16rc1-dos.tgz

From the T430 thread, you said this netbook has an Intel 945GM Express. Searching around, there is this post on setting the backlight brightness manually using setpci in Linux https://bugs.launchpad.net/ubuntu/+source/xse … 617/comments/19:

1# lspci | grep VGA
200:02.0 VGA compatible controller: Intel Corporation Mobile 945GME Express Integrated Graphics Controller (rev 03)
3# setpci -s 00:02.0 F4.B=66 (a value between 00 and FF, where FF is 100%)

This is an Intel Gen3 GPU. The author of that post has a Samsung NC10. I tried that on my ThinkPad T400 which has a Gen4 GMA 4500MHD and shows up as:

100:02.0 VGA compatible controller [0300]: Intel Corporation Mobile 4 Series Chipset Integrated Graphics Controller [8086:2a42] (rev 07) (prog-if 00 [VGA controller])

and the setpci does work.

Dropping the =<value> displays the current value. On the T400, the hotkeys provide 15 steps (and the hotkeys always work, even in Linux and DOS), the brightest corresponds to FF, second brightest is A6, and the dimmest is 06. Setting it to 0 with setpci will turn off the backlight.

For DOS, mkarcher has written dostools which can be found here: https://github.com/karcherm/dostools/releases and includes a similar PCI.EXE utility.

First check:

1C:\DOSTOOLS>pci 00:02.0
200:02.0: id 8086:2a42, class 03/00/00
3  INTA -> IRQ11

that the device at that PCI bus location is class 03, i.e. VGA compatible controller, and the PCI vendor is 8086, i.e. Intel. Your PCI device ID will be different, probably 27a6 instead of 2a42.

Then try reading the value and changing it:

1C:\DOSTOOLS>pci 00:02.0 F4
200:02.0 - f4 is 18
3C:\DOSTOOLS>pci 00:02.0 F4=2a

If it works, it should change the backlight brightness.

As always, try at your own risk. I checked the official 945G and 82G4x datasheets and the F4 register is marked reserved or not documented, respectively.

It works! Thanks jtchip.

My netbook don't have an Intel 945GM Express (945GME) but an Intel 945GM (945GM). My device ID is 27ae. I'm not sure if it also changes the gamma because with pci.exe 00:02.0 F4=01 it's barely possible to see what is on screen. F4=00 does not seem to power off screen but to remove all brightness and it's not possible to see anything.

The only problem I see is that only makes changes in memory not in BIOS, so every reboot I have to change this setting again. It's possible to change this value in BIOS?

ntalaec wrote on Yesterday, 08:21:

The only problem I see is that only makes changes in memory not in BIOS, so every reboot I have to change this setting again. It's possible to change this value in BIOS?

You can put it in your autoexec so it runs automatically

NeoG_ wrote on Yesterday, 08:27:

You can put it in your autoexec so it runs automatically

Yes, I did that. But it's possible to change value in BIOS? BIOS screen and booting before this line in AUTOEXEC.BAT it's at full brightness.

ntalaec wrote on Yesterday, 08:21:

It works! Thanks jtchip.

You're welcome. I looked up the original Linux bug and https://bugs.freedesktop.org/show_bug.cgi?id=20963#c82 says ("the method" referring to setting the F4 register):

The method this driver is using is no way Samsung specific, it's just the old legacy method. This is applicable to *all* intel chips (i830 and up). However, the driver should also program the native method (also i830 and up).

so that means it should work on the following Intel mobile chipsets:

• Gen2: Extreme Graphics (i830M), Extreme Graphics 2 (i852GM/854/855GM)
• Gen3: GMA950, GMA3150
• Gen4: GMA X3100, GMA 4500MHD

ntalaec wrote on Yesterday, 08:21:

My netbook don't have an Intel 945GM Express (945GME) but an Intel 945GM (945GM). My device ID is 27ae. I'm not sure if it also changes the gamma because with pci.exe 00:02.0 F4=01 it's barely possible to see what is on screen. F4=00 does not seem to power off screen but to remove all brightness and it's not possible to see anything.

OK, 27a6 appears to be the display controller at 00:02.1, 27ae is a "Mobile 945GSE Express Integrated Graphics Controller".
I don't think it changes the gamma, it just controls the brightness of the backlight. At F4=00, the screen is still powered on, only the backlight is turned off, it should be possible to see what's rendered on the screen if you shine a bright light on it.

ntalaec wrote on Yesterday, 08:21:

The only problem I see is that only makes changes in memory not in BIOS, so every reboot I have to change this setting again. It's possible to change this value in BIOS?

No, at least not easily. That will require BIOS modding, at least disassembling it, finding where the backlight register is set and patching it to a different value, recomputing the checksum, and flashing it. If it doesn't work, or if it leaves the computer unbootable, then that means reprogramming the EEPROM with an external programmer.

jtchip wrote on Yesterday, 23:58:

No, at least not easily. That will require BIOS modding, at least disassembling it, finding where the backlight register is set and patching it to a different value, recomputing the checksum, and flashing it. If it doesn't work, or if it leaves the computer unbootable, then that means reprogramming the EEPROM with an external programmer.

This does not sound very safe to do. But there is an utility (SANE) which claims that can reset VGA BIOS values. Maybe can change this setting too.