Re: [Qemu-ppc] [PATCH 4/4] hw/isa/i82378.c: use 1900 as a base year

[Hervé Poussineau]

Le 14/04/2019 à 20:53, Artyom Tarasenko a écrit :
> On Sun, Apr 14, 2019 at 7:01 PM Hervé Poussineau <address@hidden> wrote:
> > Le 12/04/2019 à 23:06, Artyom Tarasenko a écrit :
> > > AIX 5.1 expects the base year to be 1900. Adjust accordingly.
> > >
> > > Signed-off-by: Artyom Tarasenko <address@hidden>
> > > ---
> > >    hw/isa/i82378.c | 4 +++-
> > >    1 file changed, 3 insertions(+), 1 deletion(-)
> > >
> > > diff --git a/hw/isa/i82378.c b/hw/isa/i82378.c
> > > index a5d67bc..546c928 100644
> > > --- a/hw/isa/i82378.c
> > > +++ b/hw/isa/i82378.c
> > > @@ -107,7 +107,9 @@ static void i82378_realize(PCIDevice *pci, Error **errp)
> > >        isa = isa_create_simple(isabus, "i82374");
> > >
> > >        /* timer */
> > > -    isa_create_simple(isabus, TYPE_MC146818_RTC);
> > > +    isa = isa_create(isabus, TYPE_MC146818_RTC);
> > > +    qdev_prop_set_int32(DEVICE(isa), "base_year", 1900);
> > > +    qdev_init_nofail(DEVICE(isa));
> >
> > I am not sure the base_year should be hardcoded in i82378. I can assume other 
> > machines with a i82378 can have another base_year.
>
> I doubt it to be honest. How would it work in the hardware? Is there a
> pin which would switch a year?
> I do believe the different i823xx may have the different base years though.

OK, I don't really know. So, your patch looks fine.

Reviewed-by: Hervé Poussineau <address@hidden>

> > Maybe you can you add a base_year property to i82378, and forward it to 
> > mc146818 with object_property_add_alias?
> > Then, change 40p machine to set it to 1900, without changing it for prep 
> > machine.
>
> Were you not going to drop the -M prep ? Because I sort of dropped the
> support for it in OFW.
> I had a branch were I added some registers to -M prep  enough that it
> would be able to turn itself out as a PowerStack II Utah,
> but then again I couldn't find any advantage of having two PReP machines.
> AFAIK, the only OS which can run on Powerstack, but not on 40p is Motorola AIX.
> But since we can have IBM AIX, I don't see why would we want to keep -M prep.

I really want to drop support for prep. But, as long as prep is in code base, 
we shouldn't regress it too much.

> On the other hand, if you plan to revive it, I'll think about adding
> the support for it to OFW.
> PowerStack had a Cirrus VGA which we already have.
>
> > >    }
> > >
> > >    static void i82378_init(Object *obj)
> >
> > Hervé