Re: [Qemu-ppc] [Qemu-devel] [PATCH v2 3/3] 40p: add fixed IRQ routing for LSI SCSI device

[Mark Cave-Ayland]

On 13/09/18 15:21, Artyom Tarasenko wrote:

> On Sat, Sep 8, 2018 at 11:11 AM Mark Cave-Ayland
> <address@hidden> wrote:
>>
>> Whilst the PReP specification describes how all PCI IRQs are routed via IRQ
>> 15 on the interrupt controller, the real 40p machine has routing quirk in
>> that the LSI SCSI device is routed to IRQ 13.
> 
> Is it a routing quirk or does 40p use both 15 and 13?
> I used both in my AIX experiments and AIX seemed to be happy about it.
> But maybe AIX simply doesn't care as long as the residual data is correct.
> 
> Artyom

If you boot the Linux sandalfoot zImage then you can see the LSI IRQ
change from 15 to 13 just by changing the model name in OpenBIOS to
match that of a real 40p (compare with
http://www.juneau-lug.org/sandalfoot.php). There's also similar code
that you can see in NetBSD.

My guess would be that AIX does the "right thing" and parses the
residual data correctly as expected.


ATB,

Mark.