linux-kernel - [PATCH v4 2/5] PM: domains: Allow power-off for out-of-band wakeup-capable devices

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Message-Id: <20250922-pm-v4-v4-2-ef48428e8fe0@nxp.com>
Date: Mon, 22 Sep 2025 10:21:07 +0800
From: Peng Fan <peng.fan@....com>
To: "Rafael J. Wysocki" <rafael@...nel.org>, 
 Pavel Machek <pavel@...nel.org>, Len Brown <lenb@...nel.org>, 
 Greg Kroah-Hartman <gregkh@...uxfoundation.org>, 
 Danilo Krummrich <dakr@...nel.org>, Ulf Hansson <ulf.hansson@...aro.org>, 
 Peter Chen <peter.chen@...nel.org>, Shawn Guo <shawnguo@...nel.org>, 
 Sascha Hauer <s.hauer@...gutronix.de>, 
 Pengutronix Kernel Team <kernel@...gutronix.de>, 
 Fabio Estevam <festevam@...il.com>, 
 Thinh Nguyen <Thinh.Nguyen@...opsys.com>
Cc: linux-pm@...r.kernel.org, linux-kernel@...r.kernel.org, 
 linux-usb@...r.kernel.org, imx@...ts.linux.dev, 
 linux-arm-kernel@...ts.infradead.org, Peng Fan <peng.fan@....com>
Subject: [PATCH v4 2/5] PM: domains: Allow power-off for out-of-band
 wakeup-capable devices

Currently, if a device is configured as a system wakeup source, the PM
domain core avoids powering off its power domain during system-wide
suspend. However, this can lead to unnecessary power consumption,
especially for devices whose wakeup logic resides in an always-on domain,
i.e., devices with out-of-band wakeup capability.

To address this, add a check for device_out_band_wakeup() in
genpd_finish_suspend(). If the device supports out-of-band wakeup, its
power domain can be safely powered off, just like regular devices without
wakeup enabled. And same check in genpd_finish_resume().

This change improves power efficiency without compromising wakeup
functionality.

Signed-off-by: Peng Fan <peng.fan@....com>
---
 drivers/pmdomain/core.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/pmdomain/core.c b/drivers/pmdomain/core.c
index 61c2277c9ce39fcd2f7e77df549626e49a4d5310..4925bc1c441078a8d38600192ee696bf550e80f0 100644
--- a/drivers/pmdomain/core.c
+++ b/drivers/pmdomain/core.c
@@ -1545,7 +1545,8 @@ static int genpd_finish_suspend(struct device *dev,
 	if (ret)
 		return ret;

-	if (device_awake_path(dev) && genpd_is_active_wakeup(genpd))
+	if (device_awake_path(dev) && genpd_is_active_wakeup(genpd) &&
+	    !device_out_band_wakeup(dev))
 		return 0;

 	if (genpd->dev_ops.stop && genpd->dev_ops.start &&
@@ -1600,7 +1601,8 @@ static int genpd_finish_resume(struct device *dev,
 	if (IS_ERR(genpd))
 		return -EINVAL;

-	if (device_awake_path(dev) && genpd_is_active_wakeup(genpd))
+	if (device_awake_path(dev) && genpd_is_active_wakeup(genpd) &&
+	    !device_out_band_wakeup(dev))
 		return resume_noirq(dev);

 	genpd_lock(genpd);

-- 
2.37.1