[PATCH] genirq: do not mask interrupts by default

Never mask interrupts immediately upon request.  Disabling interrupts in
high-performance codepaths is rare, and on the other hand this change could
recover lost edges (or even other types of lost interrupts) by conservatively
only masking interrupts after they happen.  (NOTE: with this change the
highlevel irq-disable code still soft-disables this IRQ line - and if such an
interrupt happens then the IRQ flow handler keeps the IRQ masked.)

Mark i8529A controllers as 'never loses an edge'.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

2 files changed, 2 insertions, 0 deletions

diff --git a/arch/i386/kernel/i8259.c b/arch/i386/kernel/i8259.c
index 255b1af9a054..03abfdb1a6e4 100644
--- a/arch/i386/kernel/i8259.c
+++ b/arch/i386/kernel/i8259.c
@@ -41,6 +41,7 @@ static void mask_and_ack_8259A(unsigned int);
 static struct irq_chip i8259A_chip = {
         .name           = "XT-PIC",
         .mask           = disable_8259A_irq,
+        .disable        = disable_8259A_irq,
         .unmask         = enable_8259A_irq,
         .mask_ack       = mask_and_ack_8259A,
 };
diff --git a/arch/x86_64/kernel/i8259.c b/arch/x86_64/kernel/i8259.c
index d73c79e821f1..01e2cf0bdeb1 100644
--- a/arch/x86_64/kernel/i8259.c
+++ b/arch/x86_64/kernel/i8259.c
@@ -103,6 +103,7 @@ static void mask_and_ack_8259A(unsigned int);
 static struct irq_chip i8259A_chip = {
         .name           = "XT-PIC",
         .mask           = disable_8259A_irq,
+        .disable        = disable_8259A_irq,
         .unmask         = enable_8259A_irq,
         .mask_ack       = mask_and_ack_8259A,
 };