[RFC IRQ] genirq: fix handle_nested_irq for lazy disable
From: adharmap
Date: Tue Oct 26 2010 - 21:50:36 EST
From: Abhijeet Dharmapurikar <adharmap@xxxxxxxxxxxxxx>
When lazy disabling is implemented and an interrupt is disabled the
genirq code ends up marking it as IRQ_DISABLED in the descriptor.
The interrupt stays enabled in the controller. If the interrupt
fires after disabling, the flow handlers namely handle_level_irq and
handle_edge_irq mask the interrupt in the controller.
This is not the case with handle_nested_irq. The interrupt stays enabled in
the controller and if it were a level interrupt it keeps firing only to be
ignored by handle_nested_irq.
Update handle_nested_irq to mask such an interrupt.
Change-Id: Id0fa3280c49a36aa8b8db1d5cc20472bf5e53c5f
Signed-off-by: Abhijeet Dharmapurikar <adharmap@xxxxxxxxxxxxxx>
---
This problem shows up on my hardware because the interrupt controller is
over a slow bus and it doesnt deactivate the interrupt line to the processor
until an ack or mask operation is carried out for each of its active
interrupts.
I could have updated the interrupt controller thread itself to check if the
interrupt is marked IRQ_DISABLED but didn't seem right to take the
desc->lock in there. Instead updating handle_nested_irq to handle this
seemed like the right thing to do.
kernel/irq/chip.c | 10 +++++++++-
1 files changed, 9 insertions(+), 1 deletions(-)
diff --git a/kernel/irq/chip.c b/kernel/irq/chip.c
index baa5c4a..35ccc41 100644
--- a/kernel/irq/chip.c
+++ b/kernel/irq/chip.c
@@ -419,6 +419,7 @@ void handle_nested_irq(unsigned int irq)
{
struct irq_desc *desc = irq_to_desc(irq);
struct irqaction *action;
+ int mask_this_irq = 0;
irqreturn_t action_ret;
might_sleep();
@@ -428,8 +429,10 @@ void handle_nested_irq(unsigned int irq)
kstat_incr_irqs_this_cpu(irq, desc);
action = desc->action;
- if (unlikely(!action || (desc->status & IRQ_DISABLED)))
+ if (unlikely(!action || (desc->status & IRQ_DISABLED))) {
+ mask_this_irq = 1;
goto out_unlock;
+ }
desc->status |= IRQ_INPROGRESS;
raw_spin_unlock_irq(&desc->lock);
@@ -443,6 +446,11 @@ void handle_nested_irq(unsigned int irq)
out_unlock:
raw_spin_unlock_irq(&desc->lock);
+ if (unlikely(mask_this_irq)) {
+ chip_bus_lock(irq, desc);
+ desc->chip->mask(irq);
+ chip_bus_sync_unlock(irq, desc);
+ }
}
EXPORT_SYMBOL_GPL(handle_nested_irq);
--
1.7.1
Sent by an employee of the Qualcomm Innovation Center, Inc.
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum.
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