linux-kernel - threaded irq handler thread doesn't run

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Message-ID: <f861ec6f0911010505l641d07fbh4608ee4f180fbebd@mail.gmail.com>
Date:	Sun, 1 Nov 2009 14:05:44 +0100
From:	Manuel Lauss <manuel.lauss@...glemail.com>
To:	linux-kernel@...r.kernel.org
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
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