• Suresh Siddha's avatar
    x86, ioapic: Document another case when level irq is seen as an edge · 1c83995b
    Suresh Siddha authored
    In the case when cpu goes offline, fixup_irqs() will forward any
    unhandled interrupt on the offlined cpu to the new cpu
    destination that is handling the corresponding interrupt. This
    interrupt forwarding is done via IPI's. Hence, in this case also
    level-triggered io-apic interrupt will be seen as an edge
    interrupt in the cpu's APIC IRR.
    
    Document this scenario in the code which handles this case by doing
    an explicit EOI to the io-apic to clear remote IRR of the io-apic RTE.
    Requested-by: default avatarMaciej W. Rozycki <macro@linux-mips.org>
    Signed-off-by: default avatarSuresh Siddha <suresh.b.siddha@intel.com>
    Cc: Maciej W. Rozycki <macro@linux-mips.org>
    Cc: ebiederm@xmission.com
    Cc: garyhade@us.ibm.com
    LKML-Reference: <20091201233335.143970505@sbs-t61.sc.intel.com>
    Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
    1c83995b
io_apic.c 101 KB