M-VIA Known Bugs and Fixes

M-VIA 1.0 Doesn't compile with gcc 2.95.2.

Andrew Isaacson (adi@lcse.umn.edu) sent in this note and patch.

In order to compile mvia-1.0 with gcc 2.95.2, I needed to apply the
attached patch.  It updates the _set_gate macro to the one given in
linux-2.3.39/arch/i386/kernel/traps.c.  The particular bug in question
is explained at http://gcc.gnu.org/cgi-bin/fom.cgi?file=23

Without this patch, the compiler complains

/usr/bin/gcc -pipe -Wall -Wstrict-prototypes -Werror -O6 -fomit-frame-pointer -m486 -malign-loops=2
-malign-jumps=2 -malign-functions=2 -DCPU=586 -DVIA -I/usr/src/linux-2.2.12/include -D__SMP__
-I/home/adi/mvia-1.0-dist/src/vipl -DMVIA_CHAR_MAJOR=60 -include
/usr/src/linux-2.2.12/include/linux/modversions.h -D__KERNEL__ -DLINUX -DMODVERSIONS -DMODULE
-DVIPK_MAX_MAPPABLE_PAGES=4096   -c -o vipk.o vipk.c
vipk.c: In function `init_module':
vipk.c:932: Invalid `asm' statement:
vipk.c:932: fixed or forbidden register 0 (ax) was spilled for class AREG.

M-VIA 1.0 doesn't work with some Tulip cards

The symptom is that the machine crashes shortly after the driver is loaded. Several people have reported this problem, but we haven't been able to reproduce it because it is apparently hardware dependent.
M-VIA 1.0 doesn't compile with 2.4.x (or later 2.3.x) kernels

The Linux kernel version numbering scheme uses X.Y.Z where an even Y-value indicates a stable kernel and and odd Y-value indicates a development kernel. We try to keep M-VIA up to date with respect the latest stable Linux kernel and do not attempt to track all the changes which take place in the development kernels. Therefore, we will not support the 2.3.x kernels at any time.
However, there will be a new M-VIA 1.x release made for the 2.4.x kernels. However, we have no estimate for when this 2.4.x-compatible M-VIA release will be avialable.
M-VIA 1.0 and 1.1 don't honour the MVIA_DEFAULT_HOST_FILE variable in Makefile.config

The actual variable is MVIA_DEFAULT_HOSTFILE (note one less underscore). A small patch is available to fix Makefile.config and src/vipl/Makefile.
M-VIA 1.1 doesn't compile with Red Hat 7.0

The largest problem is that you must use separate compiler for kernel modules under Red Hat 7.0. You can find far more info on this page by Mike Kistler.
The VipDeregisterMem call sometimes fails when it shouldn't.

This problem was located and solved as part of the Red Hat 7.0 problems noted by Mike Kistler, above. However, this is a bug independent of what distribution you compile under. This patch corrects a cut-and-paste error in the M-VIA kernel agent.