Messages in this thread | | | Date | Mon, 10 Nov 2008 17:53:58 +0100 | From | Takashi Iwai <> | Subject | Re: [PATCH 2/3] HPET: Enter hpet_interrupt_handler with interrupts disabled |
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At Sun, 2 Nov 2008 22:23:13 +0000, Matt Fleming wrote: > > 2008/11/2 Will Newton <will.newton@gmail.com>: > > > > Combining IRQF_DISABLED and IRQF_SHARED does not reliably disable > > interrupts in the handler. Perhaps IRQF_SHARED should be removed at > > the same time? > > > > I didn't know that. Under what conditions is it unreliable?
The kernel checks IRQF_DISABLED bit of only the first handler even if multiple handlers are assigned to a single IRQ line. Thus, if another handler without IRQF_DISABLED has been already registered before yours, your IRQF_DISABLED is ignored.
See kernel/irq/handle.c.
Takashi
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