Cannot configure processor speed in KDE 4.6

[Duncan]

Dotan Cohen posted on Fri, 11 Feb 2011 11:11:30 +0200 as excerpted:

> The new KDE 4.6 power management applications do not have provision for
> adjusting the CPU speed. Because I am using a ~/.kde that was used in
> KDE 4.5 on a laptop, I am now stuck with the CPU of this KDE 4.6 desktop
> machine running at 1000 MHz, instead of it's native 2.7 MHz. I
> considered wiping to a new ~/.kde but I just have too many
> customisations in almost every KDE app to start over afresh.
> 
> How can I set the CPU speed in KDE 4.6?
> 
> Thanks!

I recall reading about that.  Apparently, "the decision was" (see how I 
did that) that it's inappropriate for "mere users" to be concerned about 
the details of power management such as CPU speeds. <shrug>

But then again, I'm obviously no "mere user", ever-since I was a kid, 
since it's a plain fact that "no user serviceable parts inside" doesn't 
apply to anyone with the slightest skills with a screwdriver and a 
replacement fuse for the inline holder (especially so if they're a 10 year 
old kid!), let alone anyone knowing how to use a soldering iron or cut-and-
splice-and-electrical-tape wires when a cord gets chewed by the dog or 
something.  So self-evidently, "user" doesn't apply to people like me.  It 
didn't then and for much the same reasons, it apparently doesn't, in this 
context either.

</rant>

To the solution, however.  What, "the bisect method" (being a regular, I'm 
sure you've seen my posts describing it before) doesn't work?  Maybe that 
"mere user" policy applies more directly to you than I thought?  (Sorry, 
the whole subject has me in a bit of a mood, now.)

Seriously, I'm absolutely a major customizer myself, so I know the 
feeling, but there's no way that'd stop me from bisecting the problem 
space down to the problem file, then likely into it, to the problem line, 
if the file itself has enough other settings to make it worthwhile, or 
simply to understand a bit more about the settings that make my system 
behave as it does.

Start by trying a fresh user to verify it's a user settings problem, then, 
assuming it is, with kde shutdown for your normal user, backup and remove 
your $KDEHOME dir (~/.kde/ by default), then start kde, to verify whether 
the problem is in $KDEHOME or elsewhere, then repeat the process, each 
time splitting the problem space in half, until you've found the culprit 
file or even setting within the file.  This bisect technique definitely 
takes a bit of patience, but little technical knowledge, and it works well 
for problems like this where the problem is either there or not (tho not 
so well for intermittent problems, since you never know for sure whether 
lack of the problem is because the test domain is clean or whether you've 
just not triggered the problem yet).

Alternatively, try a bit of brain to avoid so much brute-force iteration.  
Combined with the above, an examination of the filenames can often 
eliminate 3/4 or 7/8 of the problem-space immediately (game stats and 
config files, for instance, aren't going to be where this setting is 
found), thereby replacing a round or two of the bisect algorithm.

Or, it's not a given but there's a good chance that while the new power 
management doesn't have that option, settings are stored in the same 
place, and an strace -eopen <power-config-command>, probably piped to grep 
to eliminate most of the "haystack" and make finding the needle easier, 
could reveal the config file location directly, thus bypassing the whole 
bisect method mentioned above.

Or temporarily downgrade back to the old version and strace it, since you 
know for sure it had to store the setting somewhere.

I'd point you more directly at the file if I could, but I don't use that 
sort of powermanagement on my workstation, and I use laptop-mode-tools and 
scripted writes to the /sys/ based config files to control power 
management there, not the higher level kde stuff.  So I don't know where 
it might be, except to observe that if it's stored in the normal kde config 
locations, you'll find the file in question in either $KDEHOME/share/
config/ or in an appropriately named subdir of $KDEHOME/share/apps/.  But 
it's possible the config is stored elsewhere, possibly under ~/.config/ , 
for instance.

But stracing has a reasonable chance of getting you a result, and if not, 
bisecting has a near 100% chance.  Either way, you'll probably learn 
enough in the process to make the next time you need to find such a config 
option much easier to deal with. =:^)

-- 
Duncan - List replies preferred.   No HTML msgs.
"Every nonfree program has a lord, a master --
and if you use the program, he is your master."  Richard Stallman

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