Subject: Re: More pyxis/500a info..
To: David Hopper <>
From: Olaf Seibert <>
List: port-alpha
Date: 01/12/2000 10:41:32
On Tue 11 Jan 2000 at 10:59:44 -0800, David Hopper wrote:
> Some time ago I was going to triumphantly report that my 500a works
> perfectly with NetBS
> I can't get it to stay up long without an imminent massive corruption of
> the VGA display and an instant hard-reset.
> It's fine for a while, until I use 'vi' and begin scrolling the display
> (or do anything which touches virtual memory, it would seem).  Other
> OS's don't choke.

That looks a lot like what happens on my 433au. But only with display
access; I run mine without vga card now and it runs very stable (but I
don't do much paging it seems, swap usage is at almost 10 000 blocks

I managed to get a crash dump of such an occasion (crash upon video
access). I used another video card and it dumped me into ddb with an
"unexpected machine check", instead of a hard reboot.

Unfortunately, gdb does not trace back past the trap frame, so while I
can get a perfect backtrace of how I got into ddb after the trap, I
can't see what happened before. The ddb "trace" command has never given
me any output.

Going by what I wrote down, and output from nm, it seems like the
machine check happens somewhere in cia_swiz_mem_read_2, but that may be
not very precise.

If anybody wants the crash dump, or maybe can tell me how to manually
help gdb past the trap frame, that would be a great help. The sources
are almost vanilla 1.4.1 (but with some inactive ifdefs added to
vga-related files, so that the line numbers are off).

> I have to assume at this point that the damn pyxis bug is quite a doozy,
> and is still haunting the code.
> dhop

___ Olaf 'Rhialto' Seibert - rhialto@polder.ubc.     -- If one tells the truth,
\X/     -- one is sure, sooner or later, to be found out. (Oscar Wilde)