certain 17" monitors. Change from Michael R. Zucca, PR 4988.
XXX - This can cause problems on system with the DAFB chip which currently
use only a NuBus-based video adapter. In particular, grf devices may not be
attached properly in this case. This unfortunate situation is less annoying
than not having a reasonable console, however. A reasonable, reliable
monitor sense algorithm for the DAFB would resolve the problem.
--
When allocating bus space in bus_space_alloc(), use EX_FAST to find
the first fit in the map. The previous behavior violated the principle
of least surprise (especially annoying when you're debugging space allocation
problems). Suggested by Chris Demetriou.
(which was removed from that port not long after), as it's not
an especially meaningful test.
Also, bump the number of swap buffers allocated to 3/4 the amount
of file i/o buffers (taken from the Amiga port).
Rather than waiting indefinitely for a mouse or extended keyboard to
respond -- which may not even exist -- time out after 2 seconds and
continue. This corrects a very common problem with the MRG-based ADB
driver that has bitten many people running 1.3.
as this breaks C++ code that happens to indirectly include this header.
Both Matthias Scheler and I noticed this, independently.
This problem notably does not affect the atari and sun3/sun3x ports,
which have already implemented a similar solution.
the (in)famous MADHATTER patch. The only one that has been
tested is the Q700, however, so the rest are conditionalized
on the MADHATTER option until they can be verified.
was converted to use Mach VM for Net2/4.4BSD. The user segment table
pointer was originally stored in the PCB. When Mach VM came along,
however, it was also stored in the pmap, and loaded into the PCB in
pmap_activate(). pmap_activate() would then note that the PCB's USTP
was now in sync with the pmap's USTP, and the low-level context switch
code would use the value from the PCB.
However, pmap_activate() would also load the hardware MMU context if
the pmap was the current pmap (or, in the case where pmaps can be shared,
such as in NetBSD, if the proc was the current proc). The low-level
context switch code would then reload the hardware _again_ using the
USTP from the PCB.
However, the optimization of not calling pmap_activate() if "stchanged"
was false ended up causing some processes to use stale USTP values from
the PCB when the low-level context switch code reloaded the hardware!
This was noticed by using a real vfork(2) (which worked for some time
before failing, surprisingly!)
Since I'm hard pressed to find any real optimization here (since the
hardware was always reloaded once, sometimes twice!), the code now always
calls pmap_activate(), which uses the correct USTP value (the one in the
pmap). The PCB's USTP is now ignored, and should eventually be g/c'd.
Another optimization can actually be performed, and I have added a comment
describing what it is, but have not yet implemented it.
Also note that most of the loadustp() functions where actually incomplete.
This has been corrected. These functions should probably be split up into
MMU-specific operations, and called indirectly, rather than doing constant
run-time decision making based on values that will never change during the
course of a boot's lifetime.
scottr