used by root (the X Server) which are not locked. However, it should
deal with lost-IRQ issues on -current which I think people have been
experiencing but I am unable to reproduce (though I understand why they
would occur, because of a bug of mine). Note that most of the locking
(DRM_LOCK()/UNLOCK()) is all covered by Giant still, so it doesn't
matter yet.
- Remove locking on FreeBSD-stable and NetBSD. These are covered by the
fact that there is no reentrancy of the kernel except by interrupts,
which are locked using spldrm()/splx() instead.
DRM_*MEMORYBARRIER we had were related to an MMIO space. This means
arch-specific code on the BSDs, unfortunately. Also add
DRM_MEMORYBARRIER() and change the DRM_READMEMORYBARRIER()s that used
to be read/write barriers to it.