Bug 2835

Summary:	SCI override to 2nd IOAPIC disables interrupt on 1st IOAPIC
Product:	ACPI	Reporter:	Len Brown (lenb)
Component:	Config-Interrupts	Assignee:	Len Brown (lenb)
Status:	CLOSED CODE_FIX
Severity:	normal	CC:	acpi-bugzilla, l0new0lf, linux
Priority:	P2
Hardware:	i386
OS:	Linux
Kernel Version:	2.4.27	Subsystem:
Regression:	---	Bisected commit-id:
Attachments:	2.4 patch

Description Len Brown 2004-06-04 23:50:51 UTC

On an Intel SCB2, the ACPI SCI in IOAPIC mode is to IRQ31, 
which turns out to be pin 15 of the 2nd IOAPIC. 
 
But this causes pin15 on the 1st IOAPIC to not get initialized with 
an identify mapping because that code doesn't expect an override 
to be to an IOAPIC other than the 1st.

Comment 1 Len Brown 2004-06-05 00:02:42 UTC

Created attachment 3080 [details]
2.4 patch

This patch checks that (mp_irqs[idx].mpc_dstapic == ioapic)
before accepting that an interrupt source override should
disqualify a legacy identity mapping.  2.6 needs the same.

Comment 2 Dominik Brodowski 2004-06-20 09:39:32 UTC

This patch causes severe problems on at least some x86_64 and i386 systems: the
clock ticks twice as fast -- see, for example, http://lkml.org/lkml/2004/6/20/57

Comment 3 Len Brown 2004-06-21 12:49:05 UTC

bad fix was made into good fix 
 
2.4.27-rc1: 
http://linux.bkbits.net:8080/linux-2.4/gnupatch@40d6d35ddJnSnjsuIq54YJLwar1vhA 
linux-acpi-release-2.6.7 on the way to 2.6.8: 
http://linux-acpi.bkbits.net:8080/linux-acpi-release-2.6.7/gnupatch@40d735136IS3UC6I-LbwG91v0UYtLw

Comment 4 Len Brown 2004-07-05 21:00:32 UTC

*** Bug 2927 has been marked as a duplicate of this bug. ***