Re: IO-APIC + timer doesn't work (was: Linux 2.6.20-rc1)

[Tobias Diedrich <ranma+kernel@tdiedrich.de>]

Eric W. Biederman wrote:
> Tobias Diedrich <ranma@tdiedrich.de> writes:
> 
> > Linus Torvalds wrote:
> >
> >> Your dmesg is kind of interesting:
> >> 
> >> ..TIMER: trying IO-APIC=0 PIN=0 with 8259 IRQ0 enabled(7)APIC error on CPU0:
> > 04(40)
> >>  .. failed
> >> 
> >> where that APIC error on CPU0 seems to be a "Send accept error" and "Send 
> >> illegal vector" thing. I think we actually got the interrupt there, but 
> >> because we had some APIC setup bug, we didn't accept it properly, and it 
> >> resulted in that "APIC error" thing. Maybe. 
> >
> > I just tried changing the code so the "8259 IRQ0 enabled" case is
> > tested first and with that it boots fine.
> 
> Could you try removing the clear_IO_APIC_pin from try_io_apic_pin.
> 
> This isn't a complete fix but I believe for your hardware it will
> fix the problem and it points at what the real fix is.  
> 
> Not properly programming the io_apic for the case we want to test.

Yes, this works:

|[   27.535937] init IO_APIC IRQs
|[   27.536009]  IO-APIC (apicid-pin) 2-16, 2-17, 2-18, 2-19, 2-20, 2-21, 2-22, 2-23 not connected.
|[   27.536140] ..TIMER: trying IO-APIC=0 PIN=0 with 8259 IRQ0 disabled<3> (clear_IO_APIC_pin not called)<3> .. failed
|[   27.569357] ..TIMER: trying IO-APIC=0 PIN=0 with 8259 IRQ0 enabled<3> .. works
|[   27.602547] Using local APIC timer interrupts.

I can also report, that updating the BIOS to version 0609 (released
last week or so, also adds the long-missing HPET support) also makes
the problem go away since the first testcase then already works.
I'm currently running with the BIOS downgraded to version 0402.

|[   23.646371] ENABLING IO-APIC IRQs
|[   23.646477] init IO_APIC IRQs
|[   23.646479]  IO-APIC (apicid-pin) 2-0, 2-16, 2-17, 2-18, 2-19, 2-20, 2-21, 2-22, 2-23 not connected.
|[   23.646674] ..TIMER: trying IO-APIC=0 PIN=2 with 8259 IRQ0 disabled<3> .. works
|[   23.679872] Using local APIC timer interrupts.

Index: linux-2.6.20-rc1/arch/x86_64/kernel/io_apic.c
===================================================================
--- linux-2.6.20-rc1.orig/arch/x86_64/kernel/io_apic.c	2006-12-18 15:56:38.000000000 +0100
+++ linux-2.6.20-rc1/arch/x86_64/kernel/io_apic.c	2006-12-18 16:04:15.000000000 +0100
@@ -1586,9 +1586,11 @@
 			setup_nmi();
 			enable_8259A_irq(0);
 		}
+		apic_printk(APIC_QUIET, KERN_ERR " .. works\n");
 		return 1;
 	}
-	clear_IO_APIC_pin(apic, pin);
+	printk(KERN_ERR " (clear_IO_APIC_pin not called)");
+	/* clear_IO_APIC_pin(apic, pin); */
 	apic_printk(APIC_QUIET, KERN_ERR " .. failed\n");
 	return 0;
 }

HTH,

-- 
Tobias						PGP: http://9ac7e0bc.uguu.de
このメールは十割再利用されたビットで作られています。
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/