From: Rajat Jain <rajatja@google.com>
To: "Rafael J. Wysocki" <rjw@rjwysocki.net>,
Pavel Machek <pavel@ucw.cz>, Len Brown <len.brown@intel.com>,
linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org,
dtor@google.com, rajatxjain@gmail.com
Cc: Rajat Jain <rajatja@google.com>
Subject: [PATCH] PM / s2idle: Clear the events_check_enabled flag
Date: Thu, 10 May 2018 16:34:26 -0700 [thread overview]
Message-ID: <20180510233426.94514-1-rajatja@google.com> (raw)
In-Reply-To: <20180508230148.121852-1-rajatja@google.com>
Problem: This flag does not get cleared currently in the suspend or
resume path in the following cases:
* In case some driver's suspend routine returns an error.
* Successful s2idle case
* etc?
Why is this a problem: What happens is that the next suspend attempt
could fail even though the user did not enable the flag by writing to
/sys/power/wakeup_count. This is 1 use case how the issue can be seen
(but similar use case with driver suspend failure can be thought of):
1. Read /sys/power/wakeup_count
2. echo count > /sys/power/wakeup_count
3. echo freeze > /sys/power/wakeup_count
4. Let the system suspend, and wakeup the system using some wake source
that calls pm_wakeup_event() e.g. power button or something.
5. Note that the combined wakeup count would be incremented due
to the pm_wakeup_event() in the resume path.
6. After resuming the events_check_enabled flag is still set.
At this point if the user attempts to freeze again (without writing to
/sys/power/wakeup_count), the suspend would fail even though there has
been no wake event since the past resume.
What this patch does:
It moves the clearing of the flag to just before a resume is completed,
so that it is always cleared for the corner cases mentioned above.
Signed-off-by: Rajat Jain <rajatja@google.com>
---
kernel/power/suspend.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/kernel/power/suspend.c b/kernel/power/suspend.c
index ccd2d20e6b06..0685c4499431 100644
--- a/kernel/power/suspend.c
+++ b/kernel/power/suspend.c
@@ -437,7 +437,6 @@ static int suspend_enter(suspend_state_t state, bool *wakeup)
error = suspend_ops->enter(state);
trace_suspend_resume(TPS("machine_suspend"),
state, false);
- events_check_enabled = false;
} else if (*wakeup) {
error = -EBUSY;
}
@@ -582,6 +581,7 @@ static int enter_state(suspend_state_t state)
pm_restore_gfp_mask();
Finish:
+ events_check_enabled = false;
pm_pr_dbg("Finishing wakeup.\n");
suspend_finish();
Unlock:
--
2.15.0.403.gc27cc4dac6-goog
next prev parent reply other threads:[~2018-05-10 23:35 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-05-08 23:01 [PATCH] pci/aspm: Remove CONFIG_PCIEASPM_DEBUG Rajat Jain
2018-05-09 6:46 ` okaya
2018-05-09 9:43 ` kbuild test robot
2018-05-10 23:34 ` Rajat Jain [this message]
2018-05-10 23:36 ` [PATCH] PM / s2idle: Clear the events_check_enabled flag Rajat Jain
2018-05-10 23:39 ` [PATCH v2] pci/aspm: Remove CONFIG_PCIEASPM_DEBUG Rajat Jain
2018-06-05 22:15 ` Rajat Jain
2018-06-09 23:49 ` Sinan Kaya
2018-06-29 23:27 ` Bjorn Helgaas
2018-07-27 20:26 ` Bjorn Helgaas
2018-07-27 21:03 ` Takashi Iwai
2018-07-29 0:16 ` Sinan Kaya
2018-07-30 14:14 ` Bjorn Helgaas
2018-07-30 16:08 ` Sinan Kaya
2018-07-30 8:32 ` Lukas Wunner
2018-07-30 17:26 ` Bjorn Helgaas
2018-07-30 16:18 ` Rajat Jain
2018-07-31 8:13 ` Pali Rohár
-- strict thread matches above, loose matches on Subject: below --
2017-10-31 21:44 [PATCH] PM / s2idle: Clear the events_check_enabled flag Rajat Jain
2017-11-06 11:13 ` Pavel Machek
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