linux-kernel - [PATCH] power: Do not clear events_check_enabled in pm_wakeup

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Message-Id: <20190619175142.237794-1-ravisadineni@chromium.org>
Date:   Wed, 19 Jun 2019 10:51:42 -0700
From:   Ravi Chandra Sadineni <ravisadineni@...omium.org>
To:     rjw@...ysocki.net, len.brown@...el.com, pavel@....cz,
        gregkh@...uxfoundation.org, linux-pm@...r.kernel.org,
        linux-kernel@...r.kernel.org, tbroch@...gle.com,
        ravisadineni@...omium.org, rajatja@...gle.com
Subject: [PATCH] power: Do not clear events_check_enabled in pm_wakeup_pending()

events_check_enabled bool is set when wakeup_count sysfs attribute
is written. User level daemon is expected to write this attribute
just before suspend.

When this boolean is set, calls to pm_wakeup_event() will result in
increment of per device and global wakeup count that helps in
identifying the wake source. global wakeup count is also used by
pm_wakeup_pending() to identify if there are any pending events that
should result in an suspend abort.

Currently calls to pm_wakeup_pending() also clears events_check_enabled.
This can be a problem when there are multiple wake events or when the
suspend is aborted due to an interrupt on a shared interrupt line.
For example an Mfd device can create several platform devices which
might fetch the state on resume in the driver resume method and increment
the wakeup count if needed. But if events_check_enabled is cleared before
resume methods get to execute, wakeup count will not be incremented. Thus
let us not reset the bool here.

Note that events_check_enabled is also cleared in suspend.c/enter_state()
on every resume at the end.

Signed-off-by: Ravi Chandra Sadineni <ravisadineni@...omium.org>
---
 drivers/base/power/wakeup.c | 1 -
 1 file changed, 1 deletion(-)

diff --git a/drivers/base/power/wakeup.c b/drivers/base/power/wakeup.c
index 5b2b6a05a4f3..88aade871589 100644
--- a/drivers/base/power/wakeup.c
+++ b/drivers/base/power/wakeup.c
@@ -838,7 +838,6 @@ bool pm_wakeup_pending(void)

 		split_counters(&cnt, &inpr);
 		ret = (cnt != saved_count || inpr > 0);
-		events_check_enabled = !ret;
 	}
 	raw_spin_unlock_irqrestore(&events_lock, flags);

-- 
2.20.1