2009-11-01 13:05:41

by Manuel Lauss

[permalink] [raw]
Subject: threaded irq handler thread doesn't run

Hello!

I noticed that the thread of a threaded irq doesn't run if the interrupt
is disabled: I have a semi-broken system with 2 carddetect interrupts,
both are supposed to be edge-triggered, but due to broken PLD they
continue screaming as long as their trigger condition is met. To work
around this, the triggering one is disabled while the other gets enabled;
disabling occurs in the "fast" handler, enabling in the threaded handler:

static irqreturn_t threadfn(irq, ctx)
{
...
enable_irq(irq == cd1int ? cd2int : cd1int);
...
}

static irqreturn_t fastint(irq, ctx)
{
disable_irq_nosync(irq);
return IRQ_WAKE_THREAD;
}
...
request_threaded_irq(cd1int, fastint, threadfn, 0, "insert", ctx);
request_threaded_irq(cd2int, fastint, threadfn, 0, "eject", ctx);

In kernel/irq/manage.c::irq_thread(), the thread func isn't run
if the irq has been disabled; is there a way around this?
(removing that restriction completely solves it for me, but I
doubt this is acceptable for others).

Thanks!
Manuel Lauss