On Thu, 4 Jan 2018, Lorenzo Pieralisi wrote:

> On Tue, Jan 02, 2018 at 04:32:45PM -0500, Mikulas Patocka wrote:
> > Hi
> > 
> > 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.
> > 
> > The patch 0e4c2eeb breaks it so that I get MCE when the network card 
> > driver is loaded. The patch 814eae59 fixes the MCE, the system boot 
> > completes, but the network card doesn't receive any interrupts (and soon 
> > it reports warning about timeout on tx queue). All kernels in the 4.14 
> > branch have this bug.
> 
> I have reworked the sio code so that now the IRQ level is set upon IRQ
> mapping; patch below - it needs thorough testing since I can't test on
> alpha and I do not have in-depth knowledge of alpha platform code.
> 
> Please let me know if it fixes the issues.
> 
> Thanks !

The IDE controller doesn't receive any interrupts with this patch.

Mikulas

> -- >8 --
> diff --git a/arch/alpha/kernel/sys_sio.c b/arch/alpha/kernel/sys_sio.c
> index 37bd6d9b8eb9..e91518b6010d 100644
> --- a/arch/alpha/kernel/sys_sio.c
> +++ b/arch/alpha/kernel/sys_sio.c
> @@ -102,44 +102,48 @@ sio_pci_route(void)
>                                  alpha_mv.sys.sio.route_tab);
>  }
>  
> -static unsigned int __init
> -sio_collect_irq_levels(void)
> +static bool sio_pci_dev_irq_needs_level(const struct pci_dev *dev)
>  {
> -     unsigned int level_bits = 0;
> -     struct pci_dev *dev = NULL;
> +     if ((dev->class >> 16 == PCI_BASE_CLASS_BRIDGE) &&
> +         (dev->class >> 8 != PCI_CLASS_BRIDGE_PCMCIA))
> +             return false;
>  
> -     /* Iterate through the devices, collecting IRQ levels.  */
> -     for_each_pci_dev(dev) {
> -             if ((dev->class >> 16 == PCI_BASE_CLASS_BRIDGE) &&
> -                 (dev->class >> 8 != PCI_CLASS_BRIDGE_PCMCIA))
> -                     continue;
> +     return true;
> +}
>  
> -             if (dev->irq)
> -                     level_bits |= (1 << dev->irq);
> -     }
> -     return level_bits;
> +static void sio_fixup_irq_level(unsigned int irq)
> +{
> +     unsigned int level_bits;
> +
> +     /*
> +      * Now, make PCI interrupt level sensitive.
> +      * Notice: these registers must be accessed byte-wise. inw()/outw()
> +      * don't work.
> +      */
> +     level_bits = inb(0x4d0) | (inb(0x4d1) << 8);
> +
> +     level_bits |= (1 << irq);
> +
> +     outb((level_bits >> 0) & 0xff, 0x4d0);
> +     outb((level_bits >> 8) & 0xff, 0x4d1);
>  }
>  
> -static void __init
> -sio_fixup_irq_levels(unsigned int level_bits)
> +static void __init sio_reset_irq_levels(void)
>  {
> -     unsigned int old_level_bits;
> +     unsigned int level_bits;
>  
>       /*
> -      * Now, make all PCI interrupts level sensitive.  Notice:
> -      * these registers must be accessed byte-wise.  inw()/outw()
> +      * Notice: these registers must be accessed byte-wise. inw()/outw()
>        * don't work.
>        *
> -      * Make sure to turn off any level bits set for IRQs 9,10,11,15,
> -      *  so that the only bits getting set are for devices actually found.
> +      * Make sure to turn off any level bits set for IRQs 9,10,11,15.
>        * Note that we do preserve the remainder of the bits, which we hope
> -      *  will be set correctly by ARC/SRM.
> +      * will be set correctly by ARC/SRM.
>        *
> -      * Note: we at least preserve any level-set bits on AlphaBook1
>        */
> -     old_level_bits = inb(0x4d0) | (inb(0x4d1) << 8);
> +     level_bits = inb(0x4d0) | (inb(0x4d1) << 8);
>  
> -     level_bits |= (old_level_bits & 0x71ff);
> +     level_bits &= 0x71ff;
>  
>       outb((level_bits >> 0) & 0xff, 0x4d0);
>       outb((level_bits >> 8) & 0xff, 0x4d1);
> @@ -181,6 +185,11 @@ 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);
> +
> +     /* Fixup IRQ level if an actual IRQ mapping is detected */
> +     if (sio_pci_dev_irq_needs_level(dev) && irq > 0)
> +             sio_fixup_irq_level(irq);
> +
>       return irq >= 0 ? tmp : -1;
>  }
>  
> @@ -208,7 +217,7 @@ noname_init_pci(void)
>  {
>       common_init_pci();
>       sio_pci_route();
> -     sio_fixup_irq_levels(sio_collect_irq_levels());
> +     sio_reset_irq_levels();
>  
>       if (pc873xx_probe() == -1) {
>               printk(KERN_ERR "Probing for PC873xx Super IO chip failed.\n");
> @@ -271,8 +280,8 @@ alphabook1_init_pci(void)
>                  }
>       }
>  
> -     /* Do not set *ANY* level triggers for AlphaBook1. */
> -     sio_fixup_irq_levels(0);
> +     /* Reset level triggers for AlphaBook1. */
> +     sio_reset_irq_levels();
>  
>       /* Make sure that register PR1 indicates 1Mb mem */
>       outb(0x0f, 0x3ce); orig = inb(0x3cf);   /* read PR5  */
> 
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