SPCR

Firstly I'd like to say a big thank you to this web site, the information and recommendations here have allowed to me to succesfully build a very quiet PC. So quiet in fact that the loudest noise is now coming from one of my monitors. I read this article about monitor noise: http://www.silentpcreview.com/stop_lcd_whine
It turns out that my noise is being caused by screen brightness as described in the article. If I turn the brightness up to 100% the noise is eliminated. However that's too bright so I need to find another way to bring the brightness down aside from adjusting the backlight on the monitor itself.

The article suggests trying to reduce the brightness of the GPU's output but I'm not sure how I would do this on a Linux distro. The only available brightness adjustments that I could find are:
xrandr: This works using "xrandr --output {nameofdisplay} --brightness {value between 0 and 1}" but the results are not very good, there is substantial colour distortion using this method. As xrandr's man/manual entry states "this is a software only modification".

ACPI backlight adjustment: This doesn't work for me. I have a directory called "/sys/class/backlight/acpi_video0" and it is populated with the right files such as "brightness" but adjusting the values does nothing. I could try to fix that but I'm not sure whether this method adjusts the backlight directly on the monitor, in which case it wouldn't be that useful anyway.

GUI backlight adjustment I have a brightness slider in GNOME under the power menu. However this simply adjusts the brightness value contained in /sys/class/backlight/acpi_video0/brightness so it does not work.

My GPU is an integrated Intel HD4000 and I'm using the free Intel Xorg driver for it. The Linux distro I use is usually Debian, although I sometimes use Arch as well.

makeyourself wrote:The article suggests trying to reduce the brightness of the GPU's output but I'm not sure how I would do this on a Linux distro

Not an help, just a question: does the Intel Graphics have any control option? I'm referring to the software available here: https://01.org/linuxgraphics/downloads . Given the issues with acpi_video0, I would also check whether those info may apply to you too: http://askubuntu.com/questions/287588/u ... -on-laptop .

By the way, Merry Xmas (pun intended )!

Are you using an nvidia card with a binary blob? There used to be some good output settings in flgrx, but I noticed they were missing on my Mint17 install with 331-updates drivers.

If you are on amd (with linux? Gasp.), try in amdcccle

In either case the settings should reside in a X config file, I would guess, but I've only ever used the guis as I have no need to script it.

Edit: my bad. Failed reading comprehension. I'll check what Xorg settings are changed by fglrx when I get home and maybe they will work for you. If you get impatient, look into Xorg.conf adapter settings

If you're feeling brave and know about electronic you could lower the power going to the backlight inside the screen itself. I have done a back light repair in the past and it was trick. Only suggesting this as an option but would not say it is the best option at all.

From the arch wiki:
https://wiki.archlinux.org/index.php/backlight

There is a utility called xbacklight. In arch there is an xorg-xbacklight package. Deb probably also has one.

Arguements are "-inc 40" and "-dec 40" according to the wiki. No idea if this is 40/100, 256, etc. Also no idea what it tries to modify to accomplish the change.

The wiki has lots of other info. Maybe something in it will work.