Re: QUESTION: Network hangs with BP6 and 2.4.x kernels, hardwarerelated?

Manfred Spraul (manfred@colorfullife.com)
Fri, 12 Jan 2001 21:54:31 +0100


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Ingo Molnar wrote:
>
>
> okay - i just wanted to hear a definitive word from you that this fixes
> your problem, because this is what we'll have to do as a final solution.
> (barring any other solution.)
>
Ingo, is that possible?

The current fix is "disable_irq_nosync() and enable_irq() cause
deadlocks with level triggered ioapic irqs, do not use them" - I'm sure
ne2k-pci isn't the only driver that uses these function.

I have found one combination that doesn't hang with the unpatched
8390.c, but network throughput is down to 1/2. I hope that's due to the
debugging changes.

I'll restart now from a fresh 2.4.0 tree:
Changes:

1) enable focus cpu.
2) apply the attached patch.

I'm not sure if it's a real fix or if it just hides the problem: my
sysrq patch has shown that clearing and setting the "level trigger" bit
in the io apic reanimates the IO APIC.

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        Manfred
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--- build-2.4/arch/i386/kernel/io_apic.c.orig Fri Jan 12 20:17:36 2001 +++ build-2.4/arch/i386/kernel/io_apic.c Fri Jan 12 21:26:31 2001 @@ -134,6 +134,30 @@ spin_unlock_irqrestore(&ioapic_lock, flags); } +DO_ACTION( __trigger_level, 0, |= 0x00008000, io_apic_sync(entry->apic))/* mask = 1 */ +DO_ACTION( __trigger_edge, 0, &= 0xffff7fff, ) /* mask = 0 */ + + +static void unmask_level_IO_APIC_irq (unsigned int irq) +{ + unsigned long flags; + + spin_lock_irqsave(&ioapic_lock, flags); + __trigger_level_IO_APIC_irq(irq); + __unmask_IO_APIC_irq(irq); + spin_unlock_irqrestore(&ioapic_lock, flags); +} + +static void mask_level_IO_APIC_irq (unsigned int irq) +{ + unsigned long flags; + + spin_lock_irqsave(&ioapic_lock, flags); + __mask_IO_APIC_irq(irq); + __trigger_edge_IO_APIC_irq(irq); + spin_unlock_irqrestore(&ioapic_lock, flags); +} + static void unmask_IO_APIC_irq (unsigned int irq) { unsigned long flags; @@ -143,6 +167,7 @@ spin_unlock_irqrestore(&ioapic_lock, flags); } + void clear_IO_APIC_pin(unsigned int apic, unsigned int pin) { struct IO_APIC_route_entry entry; @@ -1181,14 +1206,14 @@ */ static unsigned int startup_level_ioapic_irq (unsigned int irq) { - unmask_IO_APIC_irq(irq); + unmask_level_IO_APIC_irq(irq); return 0; /* don't check for pending */ } -#define shutdown_level_ioapic_irq mask_IO_APIC_irq -#define enable_level_ioapic_irq unmask_IO_APIC_irq -#define disable_level_ioapic_irq mask_IO_APIC_irq +#define shutdown_level_ioapic_irq mask_level_IO_APIC_irq +#define enable_level_ioapic_irq unmask_level_IO_APIC_irq +#define disable_level_ioapic_irq mask_level_IO_APIC_irq static void end_level_ioapic_irq (unsigned int i) {

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