Re: the patch "alpha/PCI: Replace pci_fixup_irqs()" breaks networking

[Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>]

On Wed, Jan 03, 2018 at 02:05:16PM -0500, Mikulas Patocka wrote:
> 
> 
> On Wed, 3 Jan 2018, Lorenzo Pieralisi wrote:
> 
> > On Tue, Jan 02, 2018 at 11:54:47PM +0200, Meelis Roos wrote:
> > > > The patch 0e4c2eeb758a91e68b9eaf7a4bee9bd5ed97ff2b ("alpha/PCI: Replace 
> > > > pci_fixup_irqs() call with host bridge IRQ mapping hooks") breaks 
> > > > networking on Alpha for me. I have an Alpha Avanti server with tulip 
> > > > network card.
> > > 
> > > Matbe the map is wrong for Avanti? Is there some way to check that?
> > 
> > I think the problem is in noname_init_pci(), that, AFAICS, in order to set-up
> > the IRQ level, it requires IRQ mapping to be carried out. Joy.
> > 
> > See:
> > 
> > sio_fixup_irq_levels()
> > 
> > and in particular
> > 
> > sio_collect_irq_levels()
> > 
> > Does this horrid hack help (to understand where the problem is - how to
> > fix it that's another story) ? Compile tested only.
> > 
> > -- >8 --
> > diff --git a/arch/alpha/kernel/sys_sio.c b/arch/alpha/kernel/sys_sio.c
> > index 37bd6d9b8eb9..ca090307ff54 100644
> > --- a/arch/alpha/kernel/sys_sio.c
> > +++ b/arch/alpha/kernel/sys_sio.c
> > @@ -120,7 +120,7 @@ sio_collect_irq_levels(void)
> >  	return level_bits;
> >  }
> >  
> > -static void __init
> > +static void
> >  sio_fixup_irq_levels(unsigned int level_bits)
> >  {
> >  	unsigned int old_level_bits;
> > @@ -181,6 +181,14 @@ noname_map_irq(const struct pci_dev *dev, u8 slot, u8 pin)
> >  	const long min_idsel = 6, max_idsel = 14, irqs_per_slot = 5;
> >  	int irq = COMMON_TABLE_LOOKUP, tmp;
> >  	tmp = __kernel_extbl(alpha_mv.sys.sio.route_tab, irq);
> > +
> > +	if ((dev->class >> 16 != PCI_BASE_CLASS_BRIDGE) ||
> > +		    (dev->class >> 8 == PCI_CLASS_BRIDGE_PCMCIA)) {
> > +
> > +		if (irq >= 0)
> > +			sio_fixup_irq_levels(1 << tmp);
> > +	}
> > +
> >  	return irq >= 0 ? tmp : -1;
> >  }
> >  
> 
> This patch breaks it even more - so that the IDE controller doesn't 
> receive any interrupts. I can't tell if the netowrk card receives 
> interrupts or not, because it doesn't mount the root filesystem.

Yes, I expected that after having a more thorough look, that's why
I posted another patch.

Thanks,
Lorenzo