mga with default depth 16 turns computer off???

[Alex Deucher]

On Fri, Dec 20, 2013 at 4:40 AM, Felix Miata <mrmazda at earthlink.net> wrote:
> This 1.13GHz i815 Piii with G400 AGP is multiboot which I've been updating
> over the past couple of days, Fedora 21, openSUSE 12.3, 13.1 & 13.2. It's
> been reliable for years, but tonight it has been acting like the power plug
> has been pulled shortly after KDE finishes initializing my desktop. This
> happened first in 13.2 a few times with 3.11.10 kernel, so I tried and got
> same result in 13.1 with 3.11.6 kernel. Previously xorg.conf was written
> with default depth 24, but tonight I changed it to 16, and only then did the
> crashing start. I've currently booted back to 13.2 but with xorg.conf
> changed back to default depth 24 and it hasn't crashed yet. So it seems like
> 16 bit X with MGA is broken, while 24 is not. Am I missing something? I
> don't see any open bugs that look anything like this, except for one ancient
> one: https://bugs.freedesktop.org/show_bug.cgi?id=8237

If you can narrow down which component caused the problem (xserver,
mesa, mga ddx) you may be able to bisect it and figure out what caused
it.  Unfortunately mga chips are pretty old and thus not well tested
on modern software stacks these days.

Alex