I did a little research. On my machine with a 32bit system and off kdm_greet SAK is at rest, so I have not conducted further observations. Much more interesting results but I watched the 64-bit machine.
- SAK is enabled: The CPU goes to 100%.
- SAK is enabled: Switching NumLock on a PS/2 keyboard causes the death
of the keyboard - everywhere - Xorg, console. USB keyboard switching NumLock survive fine. 3. SAK is enabled: If during the time between pressing the Ctrl + Alt + Delete and SAK display window, I press the Escape, SAK behave strangely. For example, dialog Desktop Session Locked remained displayed and next pressing Ctrl + Alt + Delete keys were ignored. And then kdesktop_lock goes to 100%. 4. SAK is disabled: Switching NumLock on a PS/2 keyboard survive fine. 5. SAK is disabled: CPU goes to 20% initially, but with increasing time of inactivity increases to 80%.
So I finally disabled SAK (when I tried it first time using kcontrol it doesn't seem work, but second time ok). So I can now use kdm to login again.
As Slavek described, there is still high cpu usage. On my laptop with Pentium M 1.7 MHz undeclocked to 800MHz its 50%.
Jansky