With certain restrictions it is possible for a wakeup device to share
an IRQ with an IRQF_NO_SUSPEND user, and the warnings introduced by
commit cab303be91 are spurious. The new
IRQF_COND_SUSPEND flag allows drivers to tell the core when these
restrictions are met, allowing spurious warnings to be silenced.
This patch documents how IRQF_COND_SUSPEND is expected to be used,
updating some of the text now made invalid by its addition.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
The IRQF_NO_SUSPEND flag is intended to be used for interrupts required
to be enabled during the suspend-resume cycle. This mostly consists of
IPIs and timer interrupts, potentially including chained irqchip
interrupts if these are necessary to handle timers or IPIs. If an
interrupt does not fall into one of the aforementioned categories,
requesting it with IRQF_NO_SUSPEND is likely incorrect.
Using IRQF_NO_SUSPEND does not guarantee that the interrupt can wake the
system from a suspended state. For an interrupt to be able to trigger a
wakeup, it may be necessary to program various components of the system.
In these cases it is necessary to use {enable,disabled}_irq_wake.
Unfortunately, several drivers assume that IRQF_NO_SUSPEND ensures that
an IRQ can wake up the system, and the documentation can be read
ambiguously w.r.t. this property.
This patch updates the documentation regarding IRQF_NO_SUSPEND to make
this caveat explicit, hopefully making future misuse rarer. Cleanup of
existing misuse will occur as part of later patch series.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
This patch fix spelling typos found in Documentation/power.
Signed-off-by: Masanari Iida <standby24x7@gmail.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Add a document describing how IRQs are managed during system suspend
and resume, how wakeup interrupts work and what the IRQF_NO_SUSPEND
flag is supposed to be used for.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
