[syslinux] Syslinux 3.81-pre4 (RC): halt on idle included

[H. Peter Anvin]

Sebastian Herbszt wrote:
> 
> Still same problem (IF=0) here with Qemu and Bochs and pxelinux
> (etherboot and gpxe rom).
> Syslinux works tho.
> 

Oh, right.  This is due to a serious bug in both Etherboot and gPXE (at
least until very recent ones) where they leave interrupts disabled after
INT 1Ah and INT 15h.

I have pushed out a -pre9 which works around this problem, plus added an
STI to reset_idle which should hopefully avoid the worst instances of
the same class of problems.

I now also dump an error and debugging message if interrupts are ever
off at do_idle time.

	-hpa

-- 
H. Peter Anvin, Intel Open Source Technology Center
I work for Intel.  I don't speak on their behalf.