From 99dd5497e5be4fe4194cad181d45fd6569a930db Mon Sep 17 00:00:00 2001 From: "Liu, Chuansheng" Date: Mon, 26 Mar 2012 07:11:50 +0000 Subject: x86: Preserve lazy irq disable semantics in fixup_irqs() The default irq_disable() sematics are to mark the interrupt disabled, but keep it unmasked. If the interrupt is delivered while marked disabled, the low level interrupt handler masks it and marks it pending. This is important for detecting wakeup interrupts during suspend and for edge type interrupts to avoid losing interrupts. fixup_irqs() moves the interrupts away from an offlined cpu. For certain interrupt types it needs to mask the interrupt line before changing the affinity. After affinity has changed the interrupt line is unmasked again, but only if it is not marked disabled. This breaks the lazy irq disable semantics and causes problems in suspend as the interrupt can be lost or wakeup functionality is broken. Check irqd_irq_masked() instead of irqd_irq_disabled() because irqd_irq_masked() is only set, when the core code actually masked the interrupt line. If it's not set, we unmask the interrupt and let the lazy irq disable logic deal with an eventually incoming interrupt. [ tglx: Massaged changelog and added a comment ] Signed-off-by: liu chuansheng Cc: Yanmin Zhang Link: http://lkml.kernel.org/r/27240C0AC20F114CBF8149A2696CBE4A05DFB3@SHSMSX101.ccr.corp.intel.com Signed-off-by: Thomas Gleixner --- arch/x86/kernel/irq.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) (limited to 'arch') diff --git a/arch/x86/kernel/irq.c b/arch/x86/kernel/irq.c index 7943e0c21bde..3dafc6003b7c 100644 --- a/arch/x86/kernel/irq.c +++ b/arch/x86/kernel/irq.c @@ -282,8 +282,13 @@ void fixup_irqs(void) else if (!(warned++)) set_affinity = 0; + /* + * We unmask if the irq was not marked masked by the + * core code. That respects the lazy irq disable + * behaviour. + */ 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); -- cgit v1.2.3