sunffb

Hello,

just a question. Again. 
We finally got the sunffb driver to work on NetBSD/sparc64, including
acceleration. Turns out there was a problem in the VIS assembler code:
	 wr			%g0, 0, %fprs
this will turn off the FPU so any subsequent FPU instruction will cause
a trap. On NetBSD this led to huge numbers of traps which rendered the
Xserver unusable when acceleration was enabled.
So for NetBSD I changed this to
	 wr			%g0, 4, %fprs
to leave the FPU active and clean only the dirty bits. No more excessive
traps and things work.

Since I highly doubt this is an oversight - what's the purpose of
turning off the FPU after using VIS? Apparently the author expected the
OS to do something which NetBSD doesn't do, but what? And why? Provoking
a trap seems a rather expensive way to reset the FPU ( if that's the
purpose... )

have fun
Michael 

PS: yes, I mailed the author too

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