Messages in this thread |  | | | Date | Wed, 28 Mar 2012 18:46:13 +0530 | | From | "Srivatsa S. Bhat" <> | | Subject | Re: [PATCH] x86_fixup_irqs: Fix possible missing interrupt handle when disabling CPU |
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[ Adding a few more CCs ]
On 03/28/2012 11:08 AM, Yanmin Zhang wrote:
> On Mon, 2012-03-26 at 07:11 +0000, Liu, Chuansheng wrote: >> From: liu chuansheng <chuansheng.liu@intel.com> >> Subject: [PATCH] x86_fixup_irqs: Fix possible missing interrupt handle when disabling CPU >> >> When preparing to unmask the irq in fixup_irqs(), using irqd_irq_masked() >> as the condition to determine if do real unmasking action or not. >> >> Because in some chips, the .irq_disable is NULL, so calling disable_irq() >> does not mean the irq is masked immediately, and before enable_irq() if >> the irq is coming, it can be pending state. Using irqd_irq_disabled() will >> lose this chance. >> >> Signed-off-by: liu chuansheng <chuansheng.liu@intel.com> >> --- >> arch/x86/kernel/irq.c | 2 +- >> 1 files changed, 1 insertions(+), 1 deletions(-) >> >> diff --git a/arch/x86/kernel/irq.c b/arch/x86/kernel/irq.c >> index 6c0802e..b9dd37f 100644 >> --- a/arch/x86/kernel/irq.c >> +++ b/arch/x86/kernel/irq.c >> @@ -277,7 +277,7 @@ void fixup_irqs(void) >> set_affinity = 0; >> >> if (!irqd_can_move_in_process_context(data) && >> - !irqd_irq_disabled(data) && chip->irq_unmask) >> + !irqd_irq_masked(data) && chip->irq_unmask) >> chip->irq_unmask(data); >> >> raw_spin_unlock(&desc->lock); > Thomas, > > Originally, we found an issue when enabling Android (Gingerbread) with kernel > 2.6.35 on Medfield. > > When system goes to suspend-2-ram, some device drivers call disable_irq to > disable some device irq at device driver suspend callbacks. In addition, > some specific irq_chips just provide mask/unmask callbacks and have no > enable/disable callbacks. When drivers call > disable_irq=>...=>irq_disable=>desc->irq_data.chip->irq_disable, they don't > really mask the irq at the irq_chip. With such specific irq_chip, we could > keep the irq as wake up sources. When the irq arrives after driver disables them, > IRQ handling framework would mark it PENDING and calls the irq handler when > drivers call enable_irq. > > After device driver's suspend/suspend_noirq callbacks are called, suspend-2-ram > would disable nonboot cpus, which calls fixup_irqs. fixup_irqs really masks the irq > at irq_chip as the drivers calls disable_irq before. So one of the side effects of > calling fixup_irq is to really mask the irq and we lose the wakeup capability of > the corresponding irq. > > You might ask why drivers call disable_irq at suspend callback. That's because > another specific reason. suspend callback calls disable_irq and resume callback calls > enable_irq. Between suspend and resume callbacks, we don't want kernel to deliver > the irq to the driver irq handler as the device is not FULLY resumed yet. > > Chuangsheng's patch tries to fix above issue, to keep the difference between > enable/disable and mask/unmask callbacks of irq_chip. > > Hope my explanation could be a little clearer. > > Sorry for taking you too much time. > > Yanmin > >
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