linux-kernel - [PATCH v4 6/8] PM / sleep: Define constant for direct

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Date:   Sun, 8 Jan 2017 09:41:45 +0100
From:   Lukas Wunner <lukas@...ner.de>
To:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        linux-kernel@...r.kernel.org
Cc:     Andreas Noever <andreas.noever@...il.com>,
        linux-pci@...r.kernel.org, linux-pm@...r.kernel.org,
        Chen Yu <yu.c.chen@...el.com>,
        "Rafael J. Wysocki" <rafael.j.wysocki@...el.com>,
        Lee Jones <lee.jones@...aro.org>
Subject: [PATCH v4 6/8] PM / sleep: Define constant for direct_complete

From: Chen Yu <yu.c.chen@...el.com>

The PM core introduced the ability to keep devices runtime suspended
during the entire system sleep process with commit aae4518b3124
("PM / sleep: Mechanism to avoid resuming runtime-suspended devices
unnecessarily").

Drivers opt in to this so-called "direct_complete" mechanism by
returning a positive value from their ->prepare hook.  Usually this is
achieved with a "return 1;" statement, which looks somewhat cryptic to
readers not intimately familiar with the PM core.

Improve clarity by defining a DPM_DIRECT_COMPLETE constant which drivers
may use instead.

Suggested-by: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
Acked-by: Mika Westerberg <mika.westerberg@...ux.intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
Cc: Lee Jones <lee.jones@...aro.org>
Signed-off-by: Chen Yu <yu.c.chen@...el.com>
[LW: separate this hunk out of mfd patch, add commit message]
Signed-off-by: Lukas Wunner <lukas@...ner.de>
---
 include/linux/pm.h | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/include/linux/pm.h b/include/linux/pm.h
index f926af4..2d651a3 100644
--- a/include/linux/pm.h
+++ b/include/linux/pm.h
@@ -788,4 +788,11 @@ enum dpm_order {
 	DPM_ORDER_DEV_LAST,
 };
 
+/*
+ * Return this from system suspend/hibernation ->prepare() callback to
+ * request the core to leave the device runtime-suspended during system
+ * suspend if possible.
+ */
+#define DPM_DIRECT_COMPLETE 1
+
 #endif /* _LINUX_PM_H */
-- 
2.11.0