review-2.6.22.y/genirq-do-not-leave-interupts-enabled-on-free_irq.patch

   1 From 2cd082a9a5860afa64b032fc6df230e25d913289 Mon Sep 17 00:00:00 2001
   2 From: Thomas Gleixner <tglx@linutronix.de>
   3 Date: Wed, 20 Feb 2008 00:29:02 +0100
   4 Subject: [PATCH] genirq: do not leave interupts enabled on free_irq
   5
   6 commit 89d694b9dbe769ca1004e01db0ca43964806a611
   7
   8 The default_disable() function was changed in commit:
   9
  10  76d2160147f43f982dfe881404cfde9fd0a9da21
  11  genirq: do not mask interrupts by default
  12
  13 It removed the mask function in favour of the default delayed
  14 interrupt disabling. Unfortunately this also broke the shutdown in
  15 free_irq() when the last handler is removed from the interrupt for
  16 those architectures which rely on the default implementations. Now we
  17 can end up with a enabled interrupt line after the last handler was
  18 removed, which can result in spurious interrupts.
  19
  20 Fix this by adding a default_shutdown function, which is only
  21 installed, when the irqchip implementation does provide neither a
  22 shutdown nor a disable function.
  23
  24 Pointed-out-by: Michael Hennerich <Michael.Hennerich@analog.com>
  25 Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
  26 Acked-by: Ingo Molnar <mingo@elte.hu>
  27 Tested-by: Michael Hennerich <Michael.Hennerich@analog.com>
  28 Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
  29 Signed-off-by: Oliver Pinter <oliver.pntr@gmail.com>
  30
  31 diff --git a/kernel/irq/chip.c b/kernel/irq/chip.c
  32 index f1a73f0..7279484 100644
  33 --- a/kernel/irq/chip.c
  34 +++ b/kernel/irq/chip.c
  35 @@ -246,6 +246,17 @@ static unsigned int default_startup(unsigned int irq)
  36  }
  37
  38  /*
  39 + * default shutdown function
  40 + */
  41 +static void default_shutdown(unsigned int irq)
  42 +{
  43 +       struct irq_desc *desc = irq_desc + irq;
  44 +
  45 +       desc->chip->mask(irq);
  46 +       desc->status |= IRQ_MASKED;
  47 +}
  48 +
  49 +/*
  50   * Fixup enable/disable function pointers
  51   */
  52  void irq_chip_set_defaults(struct irq_chip *chip)
  53 @@ -256,8 +267,15 @@ void irq_chip_set_defaults(struct irq_chip *chip)
  54                 chip->disable = default_disable;
  55         if (!chip->startup)
  56                 chip->startup = default_startup;
  57 +       /*
  58 +        * We use chip->disable, when the user provided its own. When
  59 +        * we have default_disable set for chip->disable, then we need
  60 +        * to use default_shutdown, otherwise the irq line is not
  61 +        * disabled on free_irq():
  62 +        */
  63         if (!chip->shutdown)
  64 -               chip->shutdown = chip->disable;
  65 +               chip->shutdown = chip->disable != default_disable ?
  66 +                       chip->disable : default_shutdown;
  67         if (!chip->name)
  68                 chip->name = chip->typename;
  69         if (!chip->end)