linux-kernel - [RFC PATCH 0/3] genirq: mixing IRQF_NO_SUSPEND and wakeup sources on shared IRQs

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Message-Id: <1424771762-16343-1-git-send-email-boris.brezillon@free-electrons.com>
Date:	Tue, 24 Feb 2015 10:55:59 +0100
From:	Boris Brezillon <boris.brezillon@...e-electrons.com>
To:	Thomas Gleixner <tglx@...utronix.de>,
	Jason Cooper <jason@...edaemon.net>,
	"Rafael J. Wysocki" <rjw@...ysocki.net>,
	Peter Zijlstra <peterz@...radead.org>,
	Mark Rutland <mark.rutland@....com>
Cc:	linux-kernel@...r.kernel.org,
	Nicolas Ferre <nicolas.ferre@...el.com>,
	Jean-Christophe Plagniol-Villard <plagnioj@...osoft.com>,
	Alexandre Belloni <alexandre.belloni@...e-electrons.com>,
	linux-arm-kernel@...ts.infradead.org,
	Boris Brezillon <boris.brezillon@...e-electrons.com>
Subject: [RFC PATCH 0/3] genirq: mixing IRQF_NO_SUSPEND and wakeup sources on shared IRQs

Hello,

I put the IRQF_NO_SUSPEND_SAFE/IRQF_TIMER_SIBLING_OK/WHATEVER_NAME_YOU_CHOOSE
debate aside to concentrate on another problem pointed out by Rafael and
Mark: the fact that we cannot mix IRQF_NO_SUSPEND and wakeup sources on
a shared IRQ line.

This is because the wakeup code is prevailing the IRQF_NO_SUSPEND case
and will trigger a system wakeup as soon as the IRQ line is tagged as a
wakeup source.

This series propose an approach to deal with such cases by doing the
following:
1/ Prevent any system wakeup when at least one of the IRQ user has set
   the IRQF_NO_SUSPEND flag
2/ Adapt IRQ handlers so that they can safely be called in suspended
   state
3/ Let drivers decide when the system should be woken up

Let me know what you think of this approach.

Thanks,

Boris

Boris Brezillon (3):
  genirq: prevent system wakeup when dealing with IRQF_NO_SUSPEND IRQs
  genirq: add helper functions to deal with wakeup on shared
    IRQF_NO_SUSPEND IRQs
  rtc: at91sam9: properly act when IRQ handler is called in suspended
    state

 drivers/rtc/rtc-at91sam9.c | 62 ++++++++++++++++++++++++++++++++++++++--------
 include/linux/interrupt.h  |  3 +++
 kernel/irq/manage.c        | 16 ++++++++++++
 kernel/irq/pm.c            |  9 ++++++-
 4 files changed, 78 insertions(+), 12 deletions(-)

-- 
1.9.1

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