Re: Sun4/110 "Panic: Crazy Interrupts"

Hi,

> I've just tried out this patch - my P4 register reads value 0x41ffff20.

I guess that it printed the same value both times?  This probably means
that something else is generating interrupts.  It would be good to be able
to get to single user and we can work out what.

> We do get slightly further now. After cgfour and sparcvme load up, the
> screen blanks. I've been working on hooking up a serial terminal to
> try and get debug output, but no luck so far.

We disabled some of the setup for the CG4, but now I wonder if the console
device is the CG4 and that is the problem - we blank the screen and either
crash or don't unblank for some reason.  Having a serial console would be
very useful.  I'm trying to remember if the older machines will switch to
serial if the keyboard is unplugged, or they specifically have to be told
to change?  Looking at the monitor manual page:

  https://shrubbery.net/solaris9ab/SUNWaman/hman1m/monitor.1m.html

and the "SunMON PROM USAGE" section, the 'u' command should display and
set the output device.  So, maybe 'u' alone to note the settings and then
'u a' to change to serial port A.  For the 3/80, I used the 'q' command
with the values in the Field Engineer Handbook.  See the "EEPROM and NVRAM
Programming Using the Sun PROM Monitor" section, where location 0x1f has
the possible values (either 10 or 20).

Some machines need pins looped back in order to send/receive on the serial
ports.  I was using RJ45 adapters that I made up with these pinouts (copies
of the Sun parts):

  https://www.coris.org.uk/network/RJ45-serial.html

I used modular adapters like:

  https://www.ebay.com/itm/225044644595

and a rollover cable when I connected to a USB to serial adapter.

Regards,

Julian