From: Bjorn Helgaas <bhelgaas@google.com>
To: Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, "H. Peter Anvin" <hpa@zytor.com>
Cc: RalfJungralfjung-e@gmx.de, Cyrill Gorcunov <gorcunov@openvz.org>,
Yinghai Lu <yinghai@kernel.org>,
Suresh Siddha <suresh.b.siddha@intel.com>,
linux-kernel@vger.kernel.org
Subject: [PATCH 1/2] x86, ioapic: Reserve only 128 bytes for IOAPICs
Date: Thu, 25 Aug 2011 17:05:39 -0600 [thread overview]
Message-ID: <20110825230539.5355.13851.stgit@bhelgaas.mtv.corp.google.com> (raw)
Previously we reserved 1024 bytes, but that's more space than the IOAPIC
consumes, and it can cause conflicts with nearby devices. The known
requirement is 68 bytes (sizeof(struct io_apic)), and rounding up to a
power-of-2 gives us 128.
The bug reported below is caused by the following assignments (the IOAPIC
power-on default and the watchdog address recommended in the AMD SP5100
BIOS Developer's Guide):
IOAPIC[0] at [mem 0xfec00000-0xfec003ff]
SP5100 TCO timer at [mem 0xfec000f0-0xfec000f7]
Reported-by: Ralf Jung ralfjung-e@gmx.de
Reference: http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=638863
Cc: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
---
arch/x86/include/asm/apicdef.h | 7 ++++---
1 files changed, 4 insertions(+), 3 deletions(-)
diff --git a/arch/x86/include/asm/apicdef.h b/arch/x86/include/asm/apicdef.h
index 34595d5..855a18a 100644
--- a/arch/x86/include/asm/apicdef.h
+++ b/arch/x86/include/asm/apicdef.h
@@ -12,10 +12,11 @@
#define APIC_DEFAULT_PHYS_BASE 0xfee00000
/*
- * This is the IO-APIC register space as specified
- * by Intel docs:
+ * I/O APICs are accessed indirectly via an index/data pair and an EOI
+ * register. For example, see sec 13.5.1, "APIC Register Map," in the
+ * Intel ICH10 datasheet and the struct io_apic definition.
*/
-#define IO_APIC_SLOT_SIZE 1024
+#define IO_APIC_SLOT_SIZE 128
#define APIC_ID 0x20
next reply other threads:[~2011-08-25 23:05 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-08-25 23:05 Bjorn Helgaas [this message]
2011-08-25 23:05 ` [PATCH 2/2] x86, ioapic: Announce resources reserved for IOAPICs Bjorn Helgaas
2011-08-25 23:33 ` [PATCH 1/2] x86, ioapic: Reserve only 128 bytes " Suresh Siddha
2011-08-26 0:17 ` Bjorn Helgaas
2011-08-26 1:41 ` H. Peter Anvin
2011-08-26 6:18 ` Yinghai Lu
2011-08-26 6:48 ` Cyrill Gorcunov
2011-08-26 9:22 ` Ralf Jung
2011-08-26 9:39 ` Cyrill Gorcunov
2011-08-26 9:53 ` Ralf Jung
2011-08-26 9:56 ` Cyrill Gorcunov
2011-08-26 6:22 ` Cyrill Gorcunov
2011-08-26 16:21 ` Bjorn Helgaas
2011-08-26 16:24 ` H. Peter Anvin
2011-08-26 18:09 ` Cyrill Gorcunov
2011-08-26 18:21 ` H. Peter Anvin
2011-08-26 19:15 ` Cyrill Gorcunov
[not found] ` <CAErSpo5kEw=VTVv-=_D3hQg5oRNL9yEyJUnpP0biH=t3WRXMZw@mail.gmail.com>
2011-08-26 21:09 ` Fwd: " Ralf Jung
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