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Message-ID: <CAB4CAwfpO6=24tdVBtZ258hAE=sMyww-P9t1PC=BALhy3rHxSQ@mail.gmail.com>
Date: Mon, 11 May 2020 14:54:59 +0800
From: Chris Chiu <chiu@...lessm.com>
To: "Rafael J. Wysocki" <rjw@...ysocki.net>
Cc: Linux ACPI <linux-acpi@...r.kernel.org>,
Linux PM <linux-pm@...r.kernel.org>,
Zhang Rui <rui.zhang@...el.com>,
LKML <linux-kernel@...r.kernel.org>,
Todd Brandt <todd.e.brandt@...ux.intel.com>
Subject: Re: [PATCH v2] ACPI: EC: s2idle: Avoid premature returns from acpi_s2idle_wake()
On Sat, May 9, 2020 at 4:44 PM Rafael J. Wysocki <rjw@...ysocki.net> wrote:
>
> From: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
>
> If the EC GPE status is not set after checking all of the other GPEs,
> acpi_s2idle_wake() returns 'false', to indicate that the SCI event
> that has just triggered is not a system wakeup one, but it does that
> without canceling the pending wakeup and re-arming the SCI for system
> wakeup which is a mistake, because it may cause s2idle_loop() to busy
> spin until the next valid wakeup event. [If that happens, the first
> spurious wakeup is still pending after acpi_s2idle_wake() has
> returned, so s2idle_enter() does nothing, acpi_s2idle_wake()
> is called again and it sees that the SCI has triggered, but no GPEs
> are active, so 'false' is returned again, and so on.]
>
> Fix that by moving all of the GPE checking logic from
> acpi_s2idle_wake() to acpi_ec_dispatch_gpe() and making the
> latter return 'true' only if a non-EC GPE has triggered and
> 'false' otherwise, which will cause acpi_s2idle_wake() to
> cancel the pending SCI wakeup and re-arm the SCI for system
> wakeup regardless of the EC GPE status.
>
> This also addresses a lockup observed on an Elitegroup EF20EA laptop
> after attempting to wake it up from suspend-to-idle by a key press.
>
> Fixes: d5406284ff80 ("ACPI: PM: s2idle: Refine active GPEs check")
> Link: https://bugzilla.kernel.org/show_bug.cgi?id=207603
> Reported-by: Todd Brandt <todd.e.brandt@...ux.intel.com>
> Fixes: fdde0ff8590b ("ACPI: PM: s2idle: Prevent spurious SCIs from waking up the system")
> Link: https://lore.kernel.org/linux-acpi/CAB4CAwdqo7=MvyG_PE+PGVfeA17AHF5i5JucgaKqqMX6mjArbQ@mail.gmail.com/
> Reported-by: Chris Chiu <chiu@...lessm.com>
> Cc: 5.4+ <stable@...r.kernel.org> # 5.4+
> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
> ---
Tested-by: Chris Chiu <chiu@...lessm.com>
>
> -> v2:
> * Improve the changelog and add more tags.
>
> ---
> drivers/acpi/ec.c | 24 ++++++++++++++++--------
> drivers/acpi/internal.h | 1 -
> drivers/acpi/sleep.c | 14 ++------------
> 3 files changed, 18 insertions(+), 21 deletions(-)
>
> Index: linux-pm/drivers/acpi/sleep.c
> ===================================================================
> --- linux-pm.orig/drivers/acpi/sleep.c
> +++ linux-pm/drivers/acpi/sleep.c
> @@ -1013,21 +1013,11 @@ static bool acpi_s2idle_wake(void)
> if (acpi_check_wakeup_handlers())
> return true;
>
> - /*
> - * If the status bit is set for any enabled GPE other than the
> - * EC one, the wakeup is regarded as a genuine one.
> - */
> - if (acpi_ec_other_gpes_active())
> + /* Check non-EC GPE wakeups and dispatch the EC GPE. */
> + if (acpi_ec_dispatch_gpe())
> return true;
>
> /*
> - * If the EC GPE status bit has not been set, the wakeup is
> - * regarded as a spurious one.
> - */
> - if (!acpi_ec_dispatch_gpe())
> - return false;
> -
> - /*
> * Cancel the wakeup and process all pending events in case
> * there are any wakeup ones in there.
> *
> Index: linux-pm/drivers/acpi/ec.c
> ===================================================================
> --- linux-pm.orig/drivers/acpi/ec.c
> +++ linux-pm/drivers/acpi/ec.c
> @@ -1994,23 +1994,31 @@ void acpi_ec_set_gpe_wake_mask(u8 action
> acpi_set_gpe_wake_mask(NULL, first_ec->gpe, action);
> }
>
> -bool acpi_ec_other_gpes_active(void)
> -{
> - return acpi_any_gpe_status_set(first_ec ? first_ec->gpe : U32_MAX);
> -}
> -
> bool acpi_ec_dispatch_gpe(void)
> {
> u32 ret;
>
> if (!first_ec)
> + return acpi_any_gpe_status_set(U32_MAX);
> +
> + /*
> + * Report wakeup if the status bit is set for any enabled GPE other
> + * than the EC one.
> + */
> + if (acpi_any_gpe_status_set(first_ec->gpe))
> + return true;
> +
> + if (ec_no_wakeup)
> return false;
>
> + /*
> + * Dispatch the EC GPE in-band, but do not report wakeup in any case
> + * to allow the caller to process events properly after that.
> + */
> ret = acpi_dispatch_gpe(NULL, first_ec->gpe);
> - if (ret == ACPI_INTERRUPT_HANDLED) {
> + if (ret == ACPI_INTERRUPT_HANDLED)
> pm_pr_dbg("EC GPE dispatched\n");
> - return true;
> - }
> +
> return false;
> }
> #endif /* CONFIG_PM_SLEEP */
> Index: linux-pm/drivers/acpi/internal.h
> ===================================================================
> --- linux-pm.orig/drivers/acpi/internal.h
> +++ linux-pm/drivers/acpi/internal.h
> @@ -202,7 +202,6 @@ void acpi_ec_remove_query_handler(struct
>
> #ifdef CONFIG_PM_SLEEP
> void acpi_ec_flush_work(void);
> -bool acpi_ec_other_gpes_active(void);
> bool acpi_ec_dispatch_gpe(void);
> #endif
>
>
>
>
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