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    SubjectRe: [ 57/72] genirq: Unmask oneshot irqs when thread was not woken
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    Am 06.03.2012 um 21:26 schrieb Thomas Gleixner:

    > On Tue, 6 Mar 2012, Sven Joachim wrote:
    >> Am 06.03.2012 um 20:31 schrieb Thomas Gleixner:
    >>
    >> > Stephan, Sven: Can you please provide the output of /proc/interrupts ?
    >>
    >> Here is mine, from a freshly booted 3.3-rc6 kernel.
    >>
    >> Cheers,
    >> Sven
    >>
    >> CPU0
    >> 0: 25050 XT-PIC-XT-PIC timer
    >> 1: 101 XT-PIC-XT-PIC i8042
    >> 2: 0 XT-PIC-XT-PIC cascade
    >> 3: 1 XT-PIC-XT-PIC
    >> 4: 1 XT-PIC-XT-PIC
    >> 5: 0 XT-PIC-XT-PIC ehci_hcd:usb1, uhci_hcd:usb2
    >> 6: 1 XT-PIC-XT-PIC i915, uhci_hcd:usb5, yenta
    >> 7: 1 XT-PIC-XT-PIC
    >> 8: 0 XT-PIC-XT-PIC rtc0
    >> 9: 634 XT-PIC-XT-PIC acpi
    >> 10: 341 XT-PIC-XT-PIC uhci_hcd:usb4, snd_hda_intel, b43
    >
    > Ah, XT-PIC uses handle_level_irq(). /me bangs head against desk.
    >
    > Does the patch below fix the problem for you ?

    Yep, it does. Thanks!

    > ----------------->
    > Subject: genirq: Clear action->thread_mask if IRQ_ONESHOT is not set
    >
    > commit ac5637611(genirq: Unmask oneshot irqs when thread was not
    > woken) fails to unmask when a !IRQ_ONESHOT threaded handler is handled
    > by handle_level_irq. This happens because thread_mask is or'ed
    > unconditionally in irq_wake_thread(), but for !IRQ_ONESHOT interrupts
    > never cleared. So the check for !desc->thread_active fails and keeps
    > the interrupt disabled.
    >
    > Keep the thread_mask zero for !IRQ_ONESHOT interrupts.
    >
    > Reported-by: Sven Joachim <svenjoac@gmx.de>
    > Cc: stable@vger.kernel.org
    > Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
    > ---
    >
    > Index: linux-2.6/kernel/irq/manage.c
    > ===================================================================
    > --- linux-2.6.orig/kernel/irq/manage.c
    > +++ linux-2.6/kernel/irq/manage.c
    > @@ -996,11 +996,13 @@ __setup_irq(unsigned int irq, struct irq
    > * Setup the thread mask for this irqaction. Unlikely to have
    > * 32 resp 64 irqs sharing one line, but who knows.
    > */
    > - if (new->flags & IRQF_ONESHOT && thread_mask == ~0UL) {
    > - ret = -EBUSY;
    > - goto out_mask;
    > + if (new->flags & IRQF_ONESHOT) {
    > + if (thread_mask == ~0UL) {
    > + ret = -EBUSY;
    > + goto out_mask;
    > + }
    > + new->thread_mask = new->flags & IRQF_ONESHOT;
    > }
    > - new->thread_mask = 1 << ffz(thread_mask);
    >
    > if (!shared) {
    > init_waitqueue_head(&desc->wait_for_threads);


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