NetBSD and VMEbus RAM

[Chris Hanson <cmhanson%eschatologist.net@localhost>]

NetBSD has grown a bit over the years and my 32MB MVME167 appears to hit swap during execution of /etc/rc from the 9.0-stable branch. So I thought I’d try adding a RAM board.

I added a Micro Memory MM-6230 8MB board (addressed at 0xFB000000) to my system, and followed the instructions in the installation guide for telling NetBSD about it.

Unfortunately, it appears that NetBSD dies on the first access to the board as system RAM; around the time ntpd starts the system hangs and I get a yellow FAIL light on the MVME167.

I’ve confirmed that the RAM board works by writing a little program to write data to it via /dev/mem at power up, the RAM board’s parity error light comes on, and writing to it via my program clears the light, so I suspect an issue with NetBSD or something in its VME interaction.

Has anyone else had success recently with VMEbus memory boards? Where do I even begin to debug this? The board supports A32 and D32/16/8 so access itself shouldn’t be a problem. Would I be better off just writing a dumb block device driver and treating the board as a fast swap device? Did I make a mistake in leaving the board set to 0xFB000000?

  — Chris
  — who’s surprised there aren’t cheap & simple 1GB VMEbus RAM boards available

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