Confused by YaST and KDE Control Center
 

I'm running Suse 9.2 Pro (kernel 2.6.8, default) on a laptop, using KDE. I want to use the 'suspend to disk' mode, whereby contents of memory are written to disk 'as is', and from which I can resume 'as is', days later ... great if you are working on something on a laptop, and especially great if you have multiple disks - you can 'save' one working environment 'as is', fire up another hard drive, then return to the first one later.

So first I go into YaST / System / Power Management. Very logical. I see an 'Enable Suspend' button, and enable the three options 'suspend to disk', 'suspend to ram', and 'switching to standby mode'.

Next, I want to know how to actually put the computer in the desired condition - eg, suspended to disk. I see a button 'ACPI Settings', click it, and see various button assignments - eg, "power Button", and assign it to 'Suspend to Disk'. Click 'Finish', and exit Yast.

But then I see, on the 'start' menu, a 'Control Center' item, and fire it up. The menu of items presented include 'Power Control'; click it, see 'Laptop Battery'; click it, and see a bunch of tabs for 'Power Control', 'Button Actions', 'ACPI Config', etc. So I click on 'ACPI Config', and see options I'm interested in (Enable standby, enable suspend, etc) but they are grayed out, and it says to 'Setup Helper Application' to make these options available; so I look on the "Button Actions" tab instead, and it simply says 'You may need to enable ACPI suspend/resume in the ACPI panel'. Clcking 'Setup Helper Application' on the ACPI Config panel, I'm warned 'The opt/kde3/bin/klaptop_acpi_helper application does not ... have the same size or checksum as when it was compiled ...'.

Se even though I saw 'ACPI' options in YaST, I'm not seeing them in the Control Center... So that suggests the YaST methodology is different from the Control Panel methodology.

HOWEVER, in the 'tray' (lower right area of the screen) I see a battery icon, and it's the Kpowersave application. Clicking it, I see options for 'Suspend to Disk', 'Suspend to RAM', etc. And they do actually work ...

So I'm confused; what is the relationship between settings configured in YaST, Settings configured in 'Control Center', Actions performed on the 'Kpowersave' menu, etc?

Ultimately, these are all just tools to configure config files, I presume - /etc/sysconfig/powersave ...?

Thanks!

Yeah, they do just manipulate files. I don't know about powersave specifically, but generally speaking: Use YaST to work with Hardware and the system generally; Use KDE Control Center to control the GUI. That's what they're designed for (respectively).

KDE Control Center works with the ACPI and APM modules and daemons, SuSE uses Powersaved, which is why it is necessary to use YaST to configure these options.