1. 12 Jul, 2008 35 commits
  2. 11 Jul, 2008 5 commits
    • Mark Rustad's avatar
      [PATCH] IPMI: return correct value from ipmi_write · 3976df9b
      Mark Rustad authored
      This patch corrects the handling of write operations to the IPMI watchdog
      to work as intended by returning the number of characters actually
      processed. Without this patch, an "echo V >/dev/watchdog" enables the
      watchdog if IPMI is providing the watchdog function.
      Signed-off-by: default avatarMark Rustad <MRustad@gmail.com>
      Signed-off-by: default avatarCorey Minyard <cminyard@mvista.com>
      Signed-off-by: default avatarWim Van Sebroeck <wim@iguana.be>
      3976df9b
    • Ingo Molnar's avatar
      6c82a000
    • Maciej W. Rozycki's avatar
      x86: Recover timer_ack lost in the merge of the NMI watchdog · 5b4d2386
      Maciej W. Rozycki authored
      In the course of the recent unification of the NMI watchdog an assignment
      to timer_ack to switch off unnecesary POLL commands to the 8259A in the
      case of a watchdog failure has been accidentally removed.  The statement
      used to be limited to the 32-bit variation as since the rewrite of the
      timer code it has been relevant for the 82489DX only.  This change brings
      it back.
      Signed-off-by: default avatarMaciej W. Rozycki <macro@linux-mips.org>
      Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      5b4d2386
    • Maciej W. Rozycki's avatar
      x86: I/O APIC: Never configure IRQ2 · af174783
      Maciej W. Rozycki authored
      There is no such entity as ISA IRQ2.  The ACPI spec does not make it
      explicitly clear, but does not preclude it either -- all it says is ISA
      legacy interrupts are identity mapped by default (subject to overrides),
      but it does not state whether IRQ2 exists or not.  As a result if there is
      no IRQ0 override, then IRQ2 is normally initialised as an ISA interrupt,
      which implies an edge-triggered line, which is unmasked by default as this
      is what we do for edge-triggered I/O APIC interrupts so as not to miss an
      edge.
      
      To the best of my knowledge it is useless, as IRQ2 has not been in use
      since the PC/AT as back then it was taken by the 8259A cascade interrupt
      to the slave, with the line position in the slot rerouted to newly-created
      IRQ9.  No device could thus make use of this line with the pair of 8259A
      chips.  Now in theory INTIN2 of the I/O APIC may be usable, but the
      interrupt of the device wired to it would not be available in the PIC mode
      at all, so I seriously doubt if anybody decided to reuse it for a regular
      device.
      
      However there are two common uses of INTIN2.  One is for IRQ0, with an
      ACPI interrupt override (or its equivalent in the MP table).  But in this
      case IRQ2 is gone entirely with INTIN0 left vacant.  The other one is for
      an 8959A ExtINTA cascade.  In this case IRQ0 goes to INTIN0 and if ACPI is
      used INTIN2 is assumed to be IRQ2 (there is no override and ACPI has no
      way to report ExtINTA interrupts).  This is where a problem happens.
      
      The problem is INTIN2 is configured as a native APIC interrupt, with a
      vector assigned and the mask cleared.  And the line may indeed get active
      and inject interrupts if the master 8959A has its timer interrupt enabled
      (it might happen for other interrupts too, but they are normally masked in
      the process of rerouting them to the I/O APIC).  There are two cases where
      it will happen:
      
      * When the I/O APIC NMI watchdog is enabled.  This is actually a misnomer
        as the watchdog pulses are delivered through the 8259A to the LINT0
        inputs of all the local APICs in the system.  The implication is the
        output of the master 8259A goes high and low repeatedly, signalling
        interrupts to INTIN2 which is enabled too!
      
        [The origin of the name is I think for a brief period during the
        development we had a capability in our code to configure the watchdog to
        use an I/O APIC input; that would be INTIN2 in this scenario.]
      
      * When the native route of IRQ0 via INTIN0 fails for whatever reason -- as
        it happens with the system considered here.  In this scenario the timer
        pulse is delivered through the 8259A to LINT0 input of the local APIC of
        the bootstrap processor, quite similarly to how is done for the watchdog
        described above.  The result is, again, INTIN2 receives these pulses
        too.  Rafael's system used to escape this scenario, because an incorrect
        IRQ0 override would occupy INTIN2 and prevent it from being unmasked.
      
      My conclusion is IRQ2 should be excluded from configuration in all the
      cases and the current exception for ACPI systems should be lifted.  The
      reason being the exception not only being useless, but harmful as well.
      Signed-off-by: default avatarMaciej W. Rozycki <macro@linux-mips.org>
      Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
      Cc: Matthew Garrett <mjg59@srcf.ucam.org>
      Cc: Andreas Herrmann <andreas.herrmann3@amd.com>
      Cc: Stephen Rothwell <sfr@canb.auug.org.au>
      Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      af174783
    • Maciej W. Rozycki's avatar
      x86: L-APIC: Always fully configure IRQ0 · c88ac1df
      Maciej W. Rozycki authored
      Unlike the 32-bit one, the 64-bit variation of the LVT0 setup code for
      the "8259A Virtual Wire" through the local APIC timer configuration does
      not fully configure the relevant irq_chip structure.  Instead it relies on
      the preceding I/O APIC code to have set it up, which does not happen if
      the I/O APIC variants have not been tried.
      
      The patch includes corresponding changes to the 32-bit variation too
      which make them both the same, barring a small syntactic difference
      involving sequence of functions in the source.  That should work as an aid
      with the upcoming merge.
      Signed-off-by: default avatarMaciej W. Rozycki <macro@linux-mips.org>
      Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
      Cc: Matthew Garrett <mjg59@srcf.ucam.org>
      Cc: Andreas Herrmann <andreas.herrmann3@amd.com>
      Cc: Stephen Rothwell <sfr@canb.auug.org.au>
      Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      c88ac1df