linux-kernel - [PATCH 03/14] PM: domains: Don't check PM_QOS_FLAG_NO_POWER

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Date:   Wed, 11 May 2022 16:56:53 +0200
From:   Ulf Hansson <ulf.hansson@...aro.org>
To:     "Rafael J . Wysocki" <rafael@...nel.org>, linux-pm@...r.kernel.org
Cc:     "Rafael J . Wysocki" <rjw@...ysocki.net>,
        Geert Uytterhoeven <geert+renesas@...der.be>,
        Maulik Shah <quic_mkshah@...cinc.com>,
        Gabriel Fernandez <gabriel.fernandez@...s.st.com>,
        Alexandre Torgue <alexandre.torgue@...s.st.com>,
        Dmitry Osipenko <digetx@...il.com>,
        Kevin Hilman <khilman@...nel.org>,
        Ulf Hansson <ulf.hansson@...aro.org>,
        linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: [PATCH 03/14] PM: domains: Don't check PM_QOS_FLAG_NO_POWER_OFF in genpd

Back in the days when genpd supported intermediate power states of its
devices, it made sense to check the PM_QOS_FLAG_NO_POWER_OFF in
genpd_power_off(). This because the attached devices were all being put
into low power state together when the PM domain was also being powered
off.

At this point, the flag PM_QOS_FLAG_NO_POWER_OFF is better checked by
drivers from their ->runtime_suspend() callbacks, like in the
usb_port_runtime_suspend(), for example. Or perhaps an even better option
is to set the QoS resume latency constraint for the device to zero, which
informs the runtime PM core to prevent the device from being runtime
suspended.

Signed-off-by: Ulf Hansson <ulf.hansson@...aro.org>
---
 drivers/base/power/domain.c | 6 ------
 1 file changed, 6 deletions(-)

diff --git a/drivers/base/power/domain.c b/drivers/base/power/domain.c
index 262bda9b56ef..5059c5d2e64a 100644
--- a/drivers/base/power/domain.c
+++ b/drivers/base/power/domain.c
@@ -648,12 +648,6 @@ static int genpd_power_off(struct generic_pm_domain *genpd, bool one_dev_on,
 	}

 	list_for_each_entry(pdd, &genpd->dev_list, list_node) {
-		enum pm_qos_flags_status stat;
-
-		stat = dev_pm_qos_flags(pdd->dev, PM_QOS_FLAG_NO_POWER_OFF);
-		if (stat > PM_QOS_FLAGS_NONE)
-			return -EBUSY;
-
 		/*
 		 * Do not allow PM domain to be powered off, when an IRQ safe
 		 * device is part of a non-IRQ safe domain.
-- 
2.25.1