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authorThomas Gleixner <tglx@linutronix.de>2012-02-07 17:58:03 +0100
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2012-02-29 16:31:16 -0800
commitaa0eb3474beae8f6d9dcc2311dc02bea50cfd7b7 (patch)
tree2275df18ed472ad74c01ddcb8cef9909a5e9fd48 /kernel
parent72633f08ad74b93530b8e038041c450492a00ed5 (diff)
genirq: Unmask oneshot irqs when thread was not woken
commit ac5637611150281f398bb7a47e3fcb69a09e7803 upstream. When the primary handler of an interrupt which is marked IRQ_ONESHOT returns IRQ_HANDLED or IRQ_NONE, then the interrupt thread is not woken and the unmask logic of the interrupt line is never invoked. This keeps the interrupt masked forever. This was not noticed as most IRQ_ONESHOT users wake the thread unconditionally (usually because they cannot access the underlying device from hard interrupt context). Though this behaviour was nowhere documented and not necessarily intentional. Some drivers can avoid the thread wakeup in certain cases and run into the situation where the interrupt line s kept masked. Handle it gracefully. Reported-and-tested-by: Lothar Wassmann <lw@karo-electronics.de> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/irq/chip.c25
1 files changed, 23 insertions, 2 deletions
diff --git a/kernel/irq/chip.c b/kernel/irq/chip.c
index f7c543a801d9..b742edc0bdd4 100644
--- a/kernel/irq/chip.c
+++ b/kernel/irq/chip.c
@@ -330,6 +330,24 @@ out_unlock:
}
EXPORT_SYMBOL_GPL(handle_simple_irq);
+/*
+ * Called unconditionally from handle_level_irq() and only for oneshot
+ * interrupts from handle_fasteoi_irq()
+ */
+static void cond_unmask_irq(struct irq_desc *desc)
+{
+ /*
+ * We need to unmask in the following cases:
+ * - Standard level irq (IRQF_ONESHOT is not set)
+ * - Oneshot irq which did not wake the thread (caused by a
+ * spurious interrupt or a primary handler handling it
+ * completely).
+ */
+ if (!irqd_irq_disabled(&desc->irq_data) &&
+ irqd_irq_masked(&desc->irq_data) && !desc->threads_oneshot)
+ unmask_irq(desc);
+}
+
/**
* handle_level_irq - Level type irq handler
* @irq: the interrupt number
@@ -362,8 +380,8 @@ handle_level_irq(unsigned int irq, struct irq_desc *desc)
handle_irq_event(desc);
- if (!irqd_irq_disabled(&desc->irq_data) && !(desc->istate & IRQS_ONESHOT))
- unmask_irq(desc);
+ cond_unmask_irq(desc);
+
out_unlock:
raw_spin_unlock(&desc->lock);
}
@@ -417,6 +435,9 @@ handle_fasteoi_irq(unsigned int irq, struct irq_desc *desc)
preflow_handler(desc);
handle_irq_event(desc);
+ if (desc->istate & IRQS_ONESHOT)
+ cond_unmask_irq(desc);
+
out_eoi:
desc->irq_data.chip->irq_eoi(&desc->irq_data);
out_unlock: