On suspend we disable all interrupts in the core code, but this does
not mask the interrupt line in the default implementation as we use a
lazy disable approach. That means we mark the interrupt disabled, but
leave the hardware unmasked. That's an optimization because we avoid
the hardware access for the common case where no interrupt happens
after we marked it disabled. If an interrupt happens, then the
interrupt flow handler masks the line at the hardware level and marks
it pending.
Suspend makes use of this delayed disable as it "disables" all
interrupts when preparing the suspend transition. Right before the
system goes into hardware suspend state it checks whether one of the
interrupts which is marked as a wakeup interrupt came in after
disabling it.
Most interrupt chips have a separate register which selects the
interrupts which can wake up the system from suspend, so we don't have
to mask any on the non wakeup interrupts.
But now we have to deal with brilliant designed hardware which lacks
such a wakeup configuration facility. For such hardware it's necessary
to mask all non wakeup interrupts before going into suspend in order
to avoid the wakeup from random interrupts.
Rather than working around this in the affected interrupt chip
implementations we can solve this elegant in the core code itself.
Add a flag IRQCHIP_MASK_ON_SUSPEND which can be set by the irq chip
implementation to indicate, that the interrupts which are not selected
as wakeup sources must be masked in the suspend path. Mask them in the
loop which checks the wakeup interrupts pending flag.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Abhijeet Dharmapurikar <adharmap@codeaurora.org>
LKML-Reference: <alpine.LFD.2.00.1103112112310.2787@localhost6.localdomain6>
Some irq_chips need to know the state of wakeup mode for
setting the trigger type etc. Reflect it in irq_data state.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Xen needs to reenable interrupts which are marked IRQF_NO_SUSPEND in the
resume path. Add a flag to force the reenabling in the resume code.
Tested-and-acked-by: Ian Campbell <Ian.Campbell@eu.citrix.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Convert locks which cannot be sleeping locks in preempt-rt to
raw_spinlocks.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Acked-by: Ingo Molnar <mingo@elte.hu>
The kerneldoc comment describing suspend_device_irqs() is currently
misleading, because generally the function doesn't really disable
interrupt lines at the chip level. Replace it with a more accurate
one.
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
LKML-Reference: <200907050022.35117.rjw@sisk.pl>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Introduce helper functions allowing us to prevent device drivers from
getting any interrupts (without disabling interrupts on the CPU)
during suspend (or hibernation) and to make them start to receive
interrupts again during the subsequent resume. These functions make it
possible to keep timer interrupts enabled while the "late" suspend and
"early" resume callbacks provided by device drivers are being
executed. In turn, this allows device drivers' "late" suspend and
"early" resume callbacks to sleep, execute ACPI callbacks etc.
The functions introduced here will be used to rework the handling of
interrupts during suspend (hibernation) and resume. Namely,
interrupts will only be disabled on the CPU right before suspending
sysdevs, while device drivers will be prevented from receiving
interrupts, with the help of the new helper function, before their
"late" suspend callbacks run (and analogously during resume).
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Ingo Molnar <mingo@elte.hu>
Thomas Gleixner