linux-kernel - [PATCH] PM / suspend: Print the driver flags of device during suspend resume

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Message-Id: <20201023110254.26360-1-yu.c.chen@intel.com>
Date:   Fri, 23 Oct 2020 19:02:54 +0800
From:   Chen Yu <yu.c.chen@...el.com>
To:     "Rafael J. Wysocki" <rjw@...ysocki.net>,
        Len Brown <len.brown@...el.com>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Cc:     linux-pm@...r.kernel.org, linux-kernel@...r.kernel.org,
        Chen Yu <yu.c.chen@...el.com>
Subject: [PATCH] PM / suspend: Print the driver flags of device during suspend resume

Currently there are 4 driver flags to control system suspend/resume
behavior: DPM_FLAG_NO_DIRECT_COMPLETE, DPM_FLAG_SMART_PREPARE,
DPM_FLAG_SMART_SUSPEND and DPM_FLAG_MAY_SKIP_RESUME. Print these flags
during suspend resume so as to get a brief understanding of the
expected behavior of each device, and to facilitate suspend/resume
debugging/tuning.

To enable this tracing:
echo 'file drivers/base/power/main.c +p' >
/sys/kernel/debug/dynamic_debug/control

Signed-off-by: Chen Yu <yu.c.chen@...el.com>
---
 drivers/base/power/main.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/base/power/main.c b/drivers/base/power/main.c
index 205a06752ca9..be6744bdfc93 100644
--- a/drivers/base/power/main.c
+++ b/drivers/base/power/main.c
@@ -442,9 +442,9 @@ static pm_callback_t pm_noirq_op(const struct dev_pm_ops *ops, pm_message_t stat
 
 static void pm_dev_dbg(struct device *dev, pm_message_t state, const char *info)
 {
-	dev_dbg(dev, "%s%s%s\n", info, pm_verb(state.event),
+	dev_dbg(dev, "%s%s%s driver flags: %x\n", info, pm_verb(state.event),
 		((state.event & PM_EVENT_SLEEP) && device_may_wakeup(dev)) ?
-		", may wakeup" : "");
+		", may wakeup" : "", dev->power.driver_flags);
 }
 
 static void pm_dev_err(struct device *dev, pm_message_t state, const char *info,
-- 
2.17.1