kde keyboard locks

[shabbychef]

I am periodically experiencing keyboard lockups under kde 4.3.5 on amd64. Without any warning, no windows accept any keyboard focus or input. The mouse still works, and, strangely, Ctrl-Alt-F# works. I can find no other pattern. The lockups last from 1 to 5 minutes. This occurs under light usage of CPU and memory. This is a quad core machine with 8G RAM. I am using xorg-x11-7.4-r1, and nvidia-drivers-185.18.36.

how do I even start debugging this? how do I enable logging in KDE? does anybody else experience this? My google searches revealed one or two interesting hits which suggested one should, more or less, 'wait for an upgrade to kwin'. uh, ok. any help?

thanks,
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shabby