On Wed, 2009-06-24 at 07:57 +1000, Benjamin Herrenschmidt wrote:
> > I tried on a POWER3 box I have here "IBM,7044-170" and things work fine
> > here with current upstream. (I suspect a much smaller machine).
> >
> > I will really need an actual bisection here... In the meantime, I'll see
> > if I can get my hand on one of these machines here.
>
> Ok so I think we may have found it... looks like
> CONFIG_MPIC_BROKEN_REGREAD is what breaks it which is enabled by PA-Semi
> support in the .config.
>
> Can you verify that disabling PA-Semi support removes that option from
> your .config and that once removed, it works again ?
>
> We don't know yet -why- it breaks it, still investigating.
Do the following patch also fix it ?
Index: linux-work/arch/powerpc/sysdev/mpic.c
===================================================================
--- linux-work.orig/arch/powerpc/sysdev/mpic.c 2009-06-24 09:24:51.000000000
+1000
+++ linux-work/arch/powerpc/sysdev/mpic.c 2009-06-24 09:26:45.000000000
+1000
@@ -230,14 +230,16 @@ static inline u32 _mpic_irq_read(struct
{
unsigned int isu = src_no >> mpic->isu_shift;
unsigned int idx = src_no & mpic->isu_mask;
+ unsigned int val;
+ val = _mpic_read(mpic->reg_type, &mpic->isus[isu],
+ reg + (idx * MPIC_INFO(IRQ_STRIDE)));
#ifdef CONFIG_MPIC_BROKEN_REGREAD
if (reg == 0)
- return mpic->isu_reg0_shadow[idx];
- else
+ val = (val & (MPIC_VECPRI_MASK | MPIC_VECPRI_ACTIVITY)) |
+ mpic->isu_reg0_shadow[idx];
#endif
- return _mpic_read(mpic->reg_type, &mpic->isus[isu],
- reg + (idx * MPIC_INFO(IRQ_STRIDE)));
+ return val;
}
static inline void _mpic_irq_write(struct mpic *mpic, unsigned int src_no,
@@ -251,7 +253,8 @@ static inline void _mpic_irq_write(struc
#ifdef CONFIG_MPIC_BROKEN_REGREAD
if (reg == 0)
- mpic->isu_reg0_shadow[idx] = value;
+ mpic->isu_reg0_shadow[idx] =
+ value & ~(MPIC_VECPRI_MASK | MPIC_VECPRI_ACTIVITY);
#endif
}
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