linux-kernel - [PATCH] PM: domains: log failures to register always-on domains

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Message-Id: <20220929154214.7305-1-johan+linaro@kernel.org>
Date:   Thu, 29 Sep 2022 17:42:14 +0200
From:   Johan Hovold <johan+linaro@...nel.org>
To:     "Rafael J. Wysocki" <rafael@...nel.org>,
        Kevin Hilman <khilman@...nel.org>,
        Ulf Hansson <ulf.hansson@...aro.org>
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Matthias Kaehlcke <mka@...omium.org>, linux-pm@...r.kernel.org,
        linux-kernel@...r.kernel.org,
        Johan Hovold <johan+linaro@...nel.org>
Subject: [PATCH] PM: domains: log failures to register always-on domains

Always-on PM domains must be on during initialisation or the domain is
currently silently rejected.

Print an error message in case an always-on domain is not on to make it
easier to debug drivers getting this wrong (e.g. by setting an always-on
genpd flag without making sure that the state matches).

Signed-off-by: Johan Hovold <johan+linaro@...nel.org>
---
 drivers/base/power/domain.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)


Both myself and Matthias have hit this with the Qualcomm GCC drivers
when updating static genpd flags directly instead of using/adding driver
specific flags to propagate the setting.

Johan


diff --git a/drivers/base/power/domain.c b/drivers/base/power/domain.c
index bbfbf05b3446..7200e307effb 100644
--- a/drivers/base/power/domain.c
+++ b/drivers/base/power/domain.c
@@ -2087,8 +2087,10 @@ int pm_genpd_init(struct generic_pm_domain *genpd,
 
 	/* Always-on domains must be powered on at initialization. */
 	if ((genpd_is_always_on(genpd) || genpd_is_rpm_always_on(genpd)) &&
-			!genpd_status_on(genpd))
+			!genpd_status_on(genpd)) {
+		pr_err("always-on PM domain %s is not on\n", genpd->name);
 		return -EINVAL;
+	}
 
 	/* Multiple states but no governor doesn't make sense. */
 	if (!gov && genpd->state_count > 1)
-- 
2.35.1