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SubjectRe: Threaded interrupts for synaptic touchscreen in HTC dream
On Wed, Jul 22, 2009 at 11:04:33PM +0200, Thomas Gleixner wrote:
>
> Any more ?
>

Can we also have something like below by any chance?

--
Dmitry

genirq: provide dummy hard irq handler for threaded interrupts

From: Dmitry Torokhov <dmitry.torokhov@gmail.com>

Quite often drivers using threaded interrupts don't do anything
in the hard IRQ portion of their interrupt handler; everything
is offloaded to the threaded half. Instead of having every driver
implement a stub have one ready in the IRQ core.

Signed-off-by: Dmitry Torokhov <dtor@mail.ru>
---
kernel/irq/manage.c | 22 ++++++++++++++++++----
1 files changed, 18 insertions(+), 4 deletions(-)

diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c
index 50da676..cdc52f6 100644
--- a/kernel/irq/manage.c
+++ b/kernel/irq/manage.c
@@ -695,6 +695,15 @@ out_thread:
return ret;
}

+/*
+ * Default hardirq handler for threaded irqs that is used when
+ * driver did not provide its own implementation.
+ */
+static irqreturn_t dummy_hardirq_handler(int irq, void *dev_id)
+{
+ return IRQ_WAKE_THREAD;
+}
+
/**
* setup_irq - setup an interrupt
* @irq: Interrupt line to setup
@@ -837,8 +846,11 @@ EXPORT_SYMBOL(free_irq);
* request_threaded_irq - allocate an interrupt line
* @irq: Interrupt line to allocate
* @handler: Function to be called when the IRQ occurs.
- * Primary handler for threaded interrupts
- * @thread_fn: Function called from the irq handler thread
+ * Primary handler for threaded interrupts.
+ * May be NULL, in which case a dummy interrupt
+ * handler is used that simply returns
+ * IRQ_WAKE_THREAD
+ * @thread_fn: Function called from the irq handler thread.
* If NULL, no irq thread is created
* @irqflags: Interrupt type flags
* @devname: An ascii name for the claiming device
@@ -917,14 +929,16 @@ int request_threaded_irq(unsigned int irq, irq_handler_t handler,

if (desc->status & IRQ_NOREQUEST)
return -EINVAL;
- if (!handler)
+
+ if (!handler && !thread_fn) {
return -EINVAL;
+ }

action = kzalloc(sizeof(struct irqaction), GFP_KERNEL);
if (!action)
return -ENOMEM;

- action->handler = handler;
+ action->handler = handler ?: dummy_hardirq_handler;
action->thread_fn = thread_fn;
action->flags = irqflags;
action->name = devname;

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