[test patch] reliable apic lockup with one enable/disable_irq()

Manfred (manfred@colorfullife.com)
Sat, 03 Feb 2001 15:44:16 +0100


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I found a sequence that reliably locks up my 82093AA ioapic with just
one disable/enable_irq.
I've attached a patch for the tulip driver. (tested with a pnic card)

* focus cpu must be enabled.
* Gerard's mask sequence: disable_irq() only sets IRQ_DISABLED,
mask_and_ack masks the ioapic entry if an interrupt is send to a
disabled handler.
* tulip_open:

disable_irq()
<sleep>
force the irq line active (enable both TPLnkPass and TPLnkFail, one of
them is always active)
<sleep>
enable_irq()

#insmod tulip
#ifup eth1

and now the interrupt is delivered as edge triggered, but the IRR bit is
set --> irq line stuck.

Could someone test the patch with newer boards (i840, via apollo pro,
perhaps i815 if the bios builds the MP table)

I also tried changing the trigger mode bit in
{,un}mask_level_IO_APIC_irq(), but that doesn't prevent the hang.

The patch is against 2.4.1

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	Manfred
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// $Header$ // Kernel Version: // VERSION = 2 // PATCHLEVEL = 4 // SUBLEVEL = 1 // EXTRAVERSION = --- 2.4/drivers/net/tulip/tulip_core.c Sat Feb 3 14:02:54 2001 +++ build-2.4/drivers/net/tulip/tulip_core.c Sat Feb 3 14:04:58 2001 @@ -421,6 +421,24 @@ tulip_up (dev); + disable_irq(dev->irq); + set_current_state(TASK_UNINTERRUPTIBLE); + schedule_timeout(10); + +{ + long ioaddr = dev->base_addr; + long csr7 = inl(ioaddr + CSR7); + outl(NormalIntr|AbnormalIntr|TPLnkPass|TPLnkFail, ioaddr + CSR7); + set_current_state(TASK_UNINTERRUPTIBLE); + schedule_timeout(10); + enable_irq(dev->irq); + + set_current_state(TASK_UNINTERRUPTIBLE); + schedule_timeout(10); + outl(csr7, ioaddr + CSR7); + +} + netif_start_queue (dev); return 0; --- 2.4/arch/i386/kernel/io_apic.c Sat Feb 3 14:02:24 2001 +++ build-2.4/arch/i386/kernel/io_apic.c Sat Feb 3 14:54:14 2001 @@ -693,7 +693,7 @@ printk(KERN_WARNING " to linux-smp@vger.kernel.org\n"); } -void __init print_IO_APIC(void) +void print_IO_APIC(void) { int apic, i; struct IO_APIC_reg_00 reg_00; @@ -1189,14 +1189,22 @@ #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 +static void disable_level_ioapic_irq(unsigned int i) +{ + /* delayed. */ +} static void end_level_ioapic_irq (unsigned int i) { ack_APIC_irq(); } -static void mask_and_ack_level_ioapic_irq (unsigned int i) { /* nothing */ } +static void mask_and_ack_level_ioapic_irq (unsigned int i) +{ + if (irq_desc[i].status & IRQ_DISABLED) { + mask_IO_APIC_irq(i); + } +} static void set_ioapic_affinity (unsigned int irq, unsigned long mask) { --- 2.4/arch/i386/kernel/apic.c Sat Feb 3 14:02:24 2001 +++ build-2.4/arch/i386/kernel/apic.c Sat Feb 3 14:42:47 2001 @@ -270,7 +270,7 @@ * PCI Ne2000 networking cards and PII/PIII processors, dual * BX chipset. ] */ -#if 0 +#if 1 /* Enable focus processor (bit==0) */ value &= ~(1<<9); #else --- 2.4/drivers/char/sysrq.c Mon Dec 4 02:48:19 2000 +++ build-2.4/drivers/char/sysrq.c Sat Feb 3 14:33:51 2001 @@ -137,6 +137,10 @@ send_sig_all(SIGKILL, 1); orig_log_level = 8; break; + case 'q': + print_all_local_APICs(); + print_IO_APIC(); + break; default: /* Unknown: help */ if (kbd) printk("unRaw ");

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