There are some interrupts that are true edge triggered in nature. If not
marked IRQ_PENDING, when disabled, they will be lost.
Use the set_type callback to assign the correct flow type handler for
shared peripheral interrupts.
Signed-off-by: Abhijeet Dharmapurikar <[email protected]>
---
This came to light when a edge triggered interrupt was supposed to wakeup the
sytem. The flow handler was set to the default handle_level_irq. On the resume
path the flow handler was invoked right after the I bit was cleared but before
each individual interrupts were enabled. This made the handle_level_irq ignore
the interrupt (mask_ack it) and it was lost. handle_edge_irq does the right
thing by marking the interrupt as IRQ_PENDING and when the resume code gets to
enabling each interrupt this interrupt is resent again.
arch/arm/common/gic.c | 3 +++
1 files changed, 3 insertions(+), 0 deletions(-)
diff --git a/arch/arm/common/gic.c b/arch/arm/common/gic.c
index e6388dc..a83594a 100644
--- a/arch/arm/common/gic.c
+++ b/arch/arm/common/gic.c
@@ -136,6 +136,9 @@ static int gic_set_type(unsigned int irq, unsigned int type)
spin_unlock(&irq_controller_lock);
+ if ((type & IRQ_TYPE_EDGE_RISING) && gicirq > 31)
+ __set_irq_handler_unlocked(irq, handle_edge_irq);
+
return 0;
}
--
1.7.1
Sent by an employee of Qualcomm Innovation Center, Inc. Qualcomm Innovation
Center, Inc. is a member of Code Aurora Forum.
On Thu, Dec 30, 2010 at 10:59 AM, Abhijeet Dharmapurikar
<[email protected]> wrote:
> There are some interrupts that are true edge triggered in nature. If not
> marked IRQ_PENDING, when disabled, they will be lost.
>
> Use the set_type callback to assign the correct flow type handler for
> shared peripheral interrupts.
>
> Signed-off-by: Abhijeet Dharmapurikar <[email protected]>
> ---
> This came to light when a edge triggered interrupt was supposed to wakeup the
> sytem. The flow handler was set to the default handle_level_irq. On the resume
> path the flow handler was invoked right after the I bit was cleared but before
> each individual interrupts were enabled. This made the handle_level_irq ignore
Why does the flow handler hit when the interrupt is disabled? Have you set
IRQF_NOSUSPEND on this interrupt?
> the interrupt (mask_ack it) and it was lost. handle_edge_irq does the right
> thing by marking the interrupt as IRQ_PENDING and when the resume code gets to
> enabling each interrupt this interrupt is resent again.
On 12/29/2010 10:27 PM, Rabin Vincent wrote:
> On Thu, Dec 30, 2010 at 10:59 AM, Abhijeet Dharmapurikar
> <[email protected]> wrote:
>> There are some interrupts that are true edge triggered in nature. If not
>> marked IRQ_PENDING, when disabled, they will be lost.
>>
>> Use the set_type callback to assign the correct flow type handler for
>> shared peripheral interrupts.
>>
>> Signed-off-by: Abhijeet Dharmapurikar<[email protected]>
>> ---
>> This came to light when a edge triggered interrupt was supposed to wakeup the
>> sytem. The flow handler was set to the default handle_level_irq. On the resume
>> path the flow handler was invoked right after the I bit was cleared but before
>> each individual interrupts were enabled. This made the handle_level_irq ignore
>
> Why does the flow handler hit when the interrupt is disabled? Have you set
> IRQF_NOSUSPEND on this interrupt?
>
Since GIC doesnt have disable callback it implements lazy disabling. The
interrupt is only marked IRQ_DISABLED in the descriptor but is not
masked in the GIC. Hence the interrupt flow handler is hit.
Now that I re-read the code setting IRQF_NO_SUSPEND would fix the issue.
But shouldnt set_irq_wake() do something similar?
Do I need to request IRQF_NO_SUSPEND for all the interrupts that could
possibly wakeup the system - seems a bit unnecessary. IMO the interrupt
should not be disabled if it is marked IRQF_NO_SUPEND || IRQ_WAKEUP is set.
Abhijeet