Re: NetBSD and VMEbus RAM

On Aug 13, 2020, at 1:32 PM, Michael Thompson <[email protected]=
> wrote:
>=20
> =EF=BB=BF
> The MM-6230 manual says "The user must initialize the memory module to all=
ow the parity generator to store ODD parity otherwise the module will assert=
 BERR* for any subsequent read cycle."
>=20
> The first time that NetBSD reads an uninitialized location from this RAM i=
t will cause a bus error. BetBSD might scan RAM locations to see how much RA=
M is available.
>=20
> You can either write an initialization routine that writes to all memory l=
ocations on the board before NetBSD touches it, or you can move jumper E1-E2=
 to E2-E3 to prevent the board from causing a BERR*.

Indeed, I read this as well, so before installing the board yesterday I set t=
he jumpers to not generate BERR* on parity error and to auto-recover. The bo=
ard comes up with the parity error LED on, and then my program that zeroes t=
he board causes it to turn off. I did this, shut down NetBSD, specified the b=
oard addresses in 0xFFFC000[0-4], and upon reboot that=E2=80=99s when I saw t=
he failure I reported.

  =E2=80=94 Chris