Bug 1570

Summary:	IRQ 27 on an ACPI IOAPIC system with 24 IRQs
Product:	ACPI	Reporter:	Len Brown (lenb)
Component:	Config-Interrupts	Assignee:	Len Brown (lenb)
Status:	CLOSED CODE_FIX
Severity:	normal	CC:	acpi-bugzilla
Priority:	P2
Hardware:	i386
OS:	Linux
Kernel Version:	2.6.0	Subsystem:
Regression:	---	Bisected commit-id:

Description Len Brown 2003-11-21 00:20:51 UTC

The ES7000 patch added some code to arch/i386/kernel/mpparse.c 
mp_parse_prt() 
	... 
	if (!ioapic && (irq < 16)) 
		irq += 16; 
 
What happens next depends on the configuration. 
The apic and the pin# are still correct.  If the pin has been programmed already, 
then the side-effect is that entry->irq is set to the wrong number. 
If the pin needs to be programmed, then the bad irq# is used to index 
into the irq_2_pin.  If it isn't used already, then the system will still work, 
though it may report an impossible IRQ for this interrupt.  If that IRQ 
is already used, then you're probably going to have some confusion 
when the interrupt actually arrives...

Comment 1 Len Brown 2003-11-21 00:26:32 UTC

Andrew de Quincy fixed this: 
 
http://ftp.kernel.org/pub/linux/kernel/people/lenb/acpi/patches/test/2.6.0-test9/20031121014213-mpparse_es7000.patch

Comment 2 Len Brown 2004-04-12 22:19:34 UTC

Andrew's fix was integrated into 2.6.2 -- closing.