lkml.org 
[lkml]   [2011]   [Aug]   [26]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    From
    SubjectRe: Fwd: [PATCH 1/2] x86, ioapic: Reserve only 128 bytes for IOAPICs
    Date
    Tested-by: Ralf Jung <ralfjung-e@gmx.de>

    Thanks a lot!
    Ralf

    On Friday 26 August 2011 01:08:19 Bjorn Helgaas wrote:
    > FYI. I botched your email addr in the commit log.
    >
    >
    > ---------- Forwarded message ----------
    > From: Bjorn Helgaas <bhelgaas@google.com>
    > Date: Thu, Aug 25, 2011 at 5:05 PM
    > Subject: [PATCH 1/2] x86, ioapic: Reserve only 128 bytes for IOAPICs
    > 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
    >
    >
    > 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


    \
     
     \ /
      Last update: 2011-08-26 23:11    [W:0.023 / U:31.712 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site