Hard lockup switching to X from vc; Matrox G400 AGP

[Chris Rankin <rankinc@pacbell.net>]

REF: Linux 2.4.5, 2.4.4, 2.4.3 (and probably earlier);
     devfs;
     SMP (dual PIII);
     < 1GB main memory

Hi,

Has anyone noticed their Linux box lock up hard (as in cannot even be
pinged from the local network) when switching from a text vc to a vc
running X? This has happened for me even without the mga.o and
agpgart.o modules being loaded. My current workaround has been to swap
out the Matrox-supplied mga_drv.o and mga_hal_drv.o modules and
replace them with the ones from the standard X 4.03 distribution, but
these are userspace objects and shouldn't be capable of bringing the
kernel down. (Like I said, the machine can't even be pinged.)

My best guess is that the mga_hal_drv.o object is ticking an obscure
kernel bug. I am raising this with the Matrox support line as well.

Cheers,
Chris