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

Manfred Spraul
2001-01-12T20:56:58Z

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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.

--
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)
{