Hello,

I am still plagued by the random kernel lcok-ups (MCHK) since I have my
G4 processor card. Currently the best way to  improve stability is to
chance WT instead of WB. That way it may not even crash during a daily
usage for a day or two. But that is of course not the solution, the box
remains unreliable and also WT is slower than WB.

Chuck Silvers proposed to reenable WB and set powersave=0 in cpu_subr.c.
I did that for the chunk of switch() lines for the 7400 cpu since that
is what I have. I recompiled (I saw it just compiled few files, the
modified ones...) and tried the new kernel: it has the extremely strange
behavior again with the disk interrupts! It detects my cache as WB now,
but disk I/O occours only when I type on the keyboard ! Fortunately I
was able to copy back my backup kernel and reboot and everything was
fine.

But that thingle change made this strange problem appear I thought it
may be worth reporting. I am really out of ideas.

-R