linux-kernel - [PATCH 1/6] PM: runtime: enable wake irq after runtime

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Date:   Thu, 8 Apr 2021 17:35:09 +0800
From:   Chunfeng Yun <chunfeng.yun@...iatek.com>
To:     Rob Herring <robh+dt@...nel.org>,
        Mathias Nyman <mathias.nyman@...el.com>
CC:     Chunfeng Yun <chunfeng.yun@...iatek.com>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Matthias Brugger <matthias.bgg@...il.com>,
        "Rafael J. Wysocki" <rjw@...ysocki.net>,
        Len Brown <len.brown@...el.com>, Pavel Machek <pavel@....cz>,
        <linux-usb@...r.kernel.org>,
        <linux-arm-kernel@...ts.infradead.org>,
        <linux-mediatek@...ts.infradead.org>, <devicetree@...r.kernel.org>,
        <linux-kernel@...r.kernel.org>, <linux-pm@...r.kernel.org>,
        Tony Lindgren <tony@...mide.com>,
        Tianping Fang <tianping.fang@...iatek.com>,
        Eddie Hung <eddie.hung@...iatek.com>,
        Ikjoon Jang <ikjn@...omium.org>,
        Nicolas Boichat <drinkcat@...omium.org>
Subject: [PATCH 1/6] PM: runtime: enable wake irq after runtime_suspend hook called

When the dedicated wake irq is level trigger, enable it before
calling runtime_suspend, will trigger an interrupt.

e.g.
for a low level trigger type, it's low level at running time (0),
and becomes high level when enters suspend (runtime_suspend (1) is
called), a wakeup signal at (2) make it become low level, wake irq
will be triggered.

                ------------------
               |           ^     ^|
----------------           |     | --------------
 |<---(0)--->|<--(1)--|   (3)   (2)    (4)

if we enable the wake irq before calling runtime_suspend during (0),
an interrupt will arise, it causes resume immediately;
enable wake irq after calling runtime_suspend, e.g. at (3) or (4),
will works.

This patch seems no side effect on edge trigger wake irq.

Signed-off-by: Chunfeng Yun <chunfeng.yun@...iatek.com>
---
 drivers/base/power/runtime.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/drivers/base/power/runtime.c b/drivers/base/power/runtime.c
index a46a7e30881b..796739a015a5 100644
--- a/drivers/base/power/runtime.c
+++ b/drivers/base/power/runtime.c
@@ -619,12 +619,12 @@ static int rpm_suspend(struct device *dev, int rpmflags)
 	__update_runtime_status(dev, RPM_SUSPENDING);
 
 	callback = RPM_GET_CALLBACK(dev, runtime_suspend);
-
-	dev_pm_enable_wake_irq_check(dev, true);
 	retval = rpm_callback(callback, dev);
 	if (retval)
 		goto fail;
 
+	dev_pm_enable_wake_irq_check(dev, true);
+
  no_callback:
 	__update_runtime_status(dev, RPM_SUSPENDED);
 	pm_runtime_deactivate_timer(dev);
@@ -659,7 +659,6 @@ static int rpm_suspend(struct device *dev, int rpmflags)
 	return retval;
 
  fail:
-	dev_pm_disable_wake_irq_check(dev);
 	__update_runtime_status(dev, RPM_ACTIVE);
 	dev->power.deferred_resume = false;
 	wake_up_all(&dev->power.wait_queue);
-- 
2.18.0