Re: KA46/48 vsbus DMA fallthrough

[Anders Magnusson <ragge%ludd.ltu.se@localhost>]

Felix Deichmann skrev den 2015-05-09 14:26:
> Am 08.05.2015 um 23:59 schrieb Christos Zoulas:
> > But still it should not jump to NULL...
>
> While plowing through the code regarding this, I saw something else 
> that could be a missing break in a case statement in vsbus.c, 
> vsbus_attach().
>
> At least there is no /* FALLTHROUGH */ (anymore) as would be required 
> by KNF. Change vsbus.c r1.23 -> r1.24 looks strange...
> If this turns out to be an issue, VAXstations 4000 VLC and m60 (KA48 
> and KA46) would be affected.
> Are there any known problems with those machines?
>
> I have a VS 4000/60, too, and could test this, but wouldn't know how 
> to trigger a possible problem.
>
>
>     switch (vax_boardtype) {
> #if VAX49 || VAX53
>     case VAX_BTYP_53:
>     case VAX_BTYP_49:
>         sc->sc_vsregs = vax_map_physmem(VS_REGS_KA49, 1);
>         sc->sc_intreq = (char *)sc->sc_vsregs + 12;
>         sc->sc_intclr = (char *)sc->sc_vsregs + 12;
>         sc->sc_intmsk = (char *)sc->sc_vsregs + 8;
>         vsbus_dma_init(sc, 8192);
>         break;
> #endif
>
> #if VAX46 || VAX48
>     case VAX_BTYP_48:
>     case VAX_BTYP_46:
>         sc->sc_vsregs = vax_map_physmem(VS_REGS, 1);
>         sc->sc_intreq = (char *)sc->sc_vsregs + 15;
>         sc->sc_intclr = (char *)sc->sc_vsregs + 15;
>         sc->sc_intmsk = (char *)sc->sc_vsregs + 12;
>         vsbus_dma_init(sc, 32768);
> #endif
>
>     default:
>         sc->sc_vsregs = vax_map_physmem(VS_REGS, 1);
>         sc->sc_intreq = (char *)sc->sc_vsregs + 15;
>         sc->sc_intclr = (char *)sc->sc_vsregs + 15;
>         sc->sc_intmsk = (char *)sc->sc_vsregs + 12;
> [...]
This is most likely a bug, yes, but since the regs are set to the same 
values
it seems like it do not have any bad side effects.

There are a few lines below in the default case that may have some meaning,
so it is recommended to test it on one of these machines before fixing it.

-- Ragge