On 15-Sep-98 Richard van den Berg wrote:
> Hello Harald,
>> So it does on my DS5k/240 whereas on my DS5k/133 I am experiencing spurious
>> interrupts. Strange hardware :-(.
> Do you also have a Bus Error when you hit a key at the terminal, or
> do you mean that with spurious interrupts?
Yes, that's what I meant. The "official" DECstation interrupt handler, i.e. the
one that you have, doesn't take take of spurious interrupts. This results in an
"infinite" loop until a pointer reaches the end of physical memory which
triggers a Bus Error.
> Well, here it happens and
> shows on the promconsole. It is at 80085138, according to System.map
> 80085040 is decstation_handle_int and 80085164 is kn02_io_int, both in
After experiencing these Bus Errors I tracked these down to the situation that:
a) An interrupt has occured. Otherwise the interrupt handler wouldn't have been
b) The interrupt status in CP0_STATUS is 0 (zero)!
c) The interrupt status register in the IOASIC shows a serial interrupt
Strange but true. As I've said, I am still fighting with the hardware and it
doesn't look like I am making any progress :-(. Even the brute force method,
i.e. pretending those spurious interrupts *are* serial interrupts and handling
them accordingly, doesn't help.
> How do I add a printk() in assembly? :-)
Hint: include/asm-mips/asm.h. Examples: arch/mips/kernel/entry.S and head.S.
<frustrated for three weeks now>