["SOLVED"] LCD Monitor gets a lower brightness if "quiet activity"

thiagowfx · 2015-07-11 18:02:53

I'm using a desktop with Arch installed, with the i3 window manager.

Whenever I open a terminal on it, the brightness of the monitor goes down. Now, if I press the enter key continuously to make the prompt go until the middle of the screen, the brightness comes back to the normal.

I can reproduce other patterns of this 'low brightness' thing: for example, if I switch to a framebuffer (tty), the brightness also goes down. It seems to be some native power saving from the LCD monitor, which tries to save energy if the "area of activity" on the screen is relatively low.

How can I completely disable it? (I don't need it because I usually turn off the monitor when I leave the desktop)

I tried to search for Xorg, dpms and to fiddle with xset, but it seems I am missing something. Does this really have something to do with Xorg? Keyword suggestions for searching or relevant wiki entries would be appreciated.

Edit: not sure if this is relevant, but the LCD monitor is from LG: Flatron W2243S model. This one (page is in portuguese).

Last edited by thiagowfx (2015-07-14 03:28:55)

Head_on_a_Stick · 2015-07-11 18:04:09

thiagowfx wrote:

fiddle with xset

What exactly did you try?

For example:

xset -dpms

thiagowfx · 2015-07-11 18:09:44

I tried things such as:

xset dpms force off
xset dpms force standby
xset f off (note: this is not really useful I guess, because the problem is not the screen going completely blank)

I hand't tried "xset -dpms" before, but just tried it now, and it seems to have no effect whatsoever.

I'm not sure if DPMS is the culprit, I'm just suspecting the problem has something to do with it.

Edit: tried suggestions of this topic too.

Last edited by thiagowfx (2015-07-11 18:13:03)

Head_on_a_Stick · 2015-07-11 18:15:47

Do the brightness values in /sys/class/backlight/{<card name>_backlight,acpi_backlight}/brightness change when the screen dims?

If not, the monitor itself is dimming.

thiagowfx · 2015-07-11 18:24:38

/sys/class/backlight is empty here. Maybe this is only present in a laptop?

Hum, unfortunalely there seems to be no option in the monitor menu / setup related to dimming / power saving.

Head_on_a_Stick · 2015-07-11 18:29:01

thiagowfx wrote:

/sys/class/backlight is empty here. Maybe this is only present in a laptop?

D'oh!

Sorry yes, you are quite correct...

I think this is down to your monitor but I don't know why or how to fix it (I've only ever owned laptops)

thiagowfx · 2015-07-14 03:28:15

Just a quick update...now the monitor is how I want it to be. I'm not sure how I achieved that...maybe one of those commands worked, after all. Or maybe it was some config in the menu of the monitor I accidentally stumbled upon and changed without realizing it was the correct one -- although I remember seeing nothing related to power saving in there.

Er...I guess I'll mark the topic as solved then. Hopefully I won't need to re-install Arch in this machine so this issue could arise again. Thanks for the support, Head_on_a_Stick.

Arch Linux

#1 2015-07-11 18:02:53

["SOLVED"] LCD Monitor gets a lower brightness if "quiet activity"

#2 2015-07-11 18:04:09

Re: ["SOLVED"] LCD Monitor gets a lower brightness if "quiet activity"

#3 2015-07-11 18:09:44

Re: ["SOLVED"] LCD Monitor gets a lower brightness if "quiet activity"

#4 2015-07-11 18:15:47

Re: ["SOLVED"] LCD Monitor gets a lower brightness if "quiet activity"

#5 2015-07-11 18:24:38

Re: ["SOLVED"] LCD Monitor gets a lower brightness if "quiet activity"

#6 2015-07-11 18:29:01

Re: ["SOLVED"] LCD Monitor gets a lower brightness if "quiet activity"

#7 2015-07-14 03:28:15

Re: ["SOLVED"] LCD Monitor gets a lower brightness if "quiet activity"

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