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From:   Chris Chiu <chiu@endlessm.com>
Date:   Tue, 5 May 2020 01:09:30 +0800
Message-ID: <CAB4CAwdqo7=MvyG_PE+PGVfeA17AHF5i5JucgaKqqMX6mjArbQ@mail.gmail.com>
Subject: System fails to exit s2idle by a keystroke on my laptop
To:     "Rafael J. Wysocki" <rjw@rjwysocki.net>,
        seth.forshee@canonical.com, Len Brown <lenb@kernel.org>
Cc:     ACPI Devel Maling List <linux-acpi@vger.kernel.org>,
        Linux Kernel <linux-kernel@vger.kernel.org>,
        Linux Upstreaming Team <linux@endlessm.com>
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Hi,
    I have an Intel X5-Z8350 laptop which used to work fine on s2idle
enter/exit with kernel 5.3. After upgrading to kernel 5.4 and later,
the system can still exit s2idle by power button. However, if I try to
wake it up from a keystroke, the system will freeze and then no longer
respond even to the power button. I can only shut it down and power on
again.

    I tried to 'git bisect' to find out which commit causes the
difference, it shows me the commit "ACPI: PM: s2idle: Prevent spurious
SCIs from waking up the system". My laptop can work as usual to exit
s2idle by a keystroke with reverting it on kernel 5.4.

    Then I tried to check whether I can reproduce it on the latest
mainline kernel, the same problem still there. But I can not fix it by
simply reverting. I found the acpi_s2idle_wake() has been refined on
the latest mainline kernel, and I have to make modifications as
follows to make my laptop work.

@@ -1024,7 +1024,7 @@ static bool acpi_s2idle_wake(void)
                 * regarded as a spurious one.
                 */
                if (!acpi_ec_dispatch_gpe())
-                       return false;
+                       return true;

                /*
                 * Cancel the wakeup and process all pending events in case

    Maybe there's something special on my laptop so a keystroke is
considered as a spurious event on this machine? Don't know if the DSDT
helps or not.
https://gist.github.com/mschiu77/de8af6da78be12cf442853e7747f76ed

    Please let me know if there's anything I can help to address this
problem. Thanks

Chris