Strange Problem with Power Management

[joany]

Once in a while when the planets are in a certain alignment, the Power Management feature will decide to dim my display after a time delay. Checking Settings > Power Management shows the Dim Display feature is turned "off" (unticked). But once this dimming behavior starts, the only way to turn it off is to tick Dim Display (set to 10 minutes), click Apply, then untick Dim Display and click Apply again.

When Dim Display decides to activate itself, it usually does it on bootup. But once in a while, it will activate in the middle of the afternoon after the system has been running for several hours. Ticking and unticking the Dim Display setting (and clicking the Apply button in between) does get everything back to normal, but it's irritating.

Has anyone else seen this behavior?

[uncle mark]

Has anyone else seen this behavior?

Not since I quit drinking.

[m_pav]

Yes, similar issue briefly during one of my hard disk installs to test my personal build, but this was short lived and righted itself by using the laptops display brightness Function keys. That was this year, but I have seen it before then when I was running M11, though not frequent enough to be of a concern.

I guess with a desktop, you don't have the function keys to adjust display brightness, so it would be more of an issue. Maybe you could try to create a key combo that would mimic a laptops function keys to achieve the same task?

[joany]

I guess with a desktop, you don't have the function keys to adjust display brightness, so it would be more of an issue. Maybe you could try to create a key combo that would mimic a laptops function keys to achieve the same task?

No, there are no keyboard functions that control display brightness. Even if there were, they probably would only work with Windows, which is the case for most of the other special function keys on this particular HP desktop.

I don't think the problem involves the brightness setting but rather the fact that the screensaver (aka Dim Display) randomly turns itself on. When I referred to the Dim Display setting, I meant the setting in Power Management that actually turns the display completely OFF after a time delay. I think "Dim Display" and "Screen Saver" mean the same thing, but I'm not 100% sure.

Another other thing I noticed is that System Settings > Startup and Shutdown > Service Manager shows Power Management as "off" when I launching System Settings using "kdesu systemsettings". This means all of the Power Management settings are disabled in the root System Settings, and they're only activated in the user System Settings. I'm pretty sure this isn't a problem, but I thought I'd mention it.

I don't remember any screen saver anomalies with MEPIS. This seems to only affect the MX-14/KDE installation.

[m_pav]

Actually, the screen brightness controls are often one of the items that work very well in Laptops, so if a Desktop has the possibility of using the functions, then they will most likely work.

Here's the terminal output from my laptop showing the key presses for changing the display brightness, I have added in blank lines for clarity.
michael@mikepav:~
$ showkey -k

keycode 28 release
keycode 143 press
keycode 224 press
keycode 224 release
keycode 143 release

keycode 143 press
keycode 225 press
keycode 225 release
keycode 143 release

Keycode 28 release is the enter key, it recognises I have released the key.
keycode 143 is my laptops function key to activate the dual functions of these keys.
Keycode 224 is dim the backlight by 1 point
keycode 225 is increase the backlight by 1 point

The help for the keycode tool says the numbers are always the same for the keys functions, so test yours to see if they match up, and if they do, you can map a function to a number and achieve what may not have been possible before. You'll have to switch to a virtual terminal to get out of X or the command will not work.

Number keys above the letters,
1 = 2, 2 = 3, sequential numbers through to 9 = 10, 0 = 11
Number keys on the number pad
1 = 79
2 = 80
3 = 81
4 = 75
5 = 76
6 = 77
7 = 71
8 = 72
9 = 73
0 = 82
. = 83
Alphanumeric keys
q = 16, w = 17 sequential numbers through to p = 25
a = 30, s = 31, sequential numbers through to l = 38

Essentially, if you can map a key sequence to 224, you'll have a dim backlight option, and 225 will brighten the backlight.

Food for thought.

[jdmeaux1952]

...
Food for thought.

Not the kind of food I was thinking about this morning. More like, food for tummy.