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From: Anshuman Khandual <anshuman.khandual@arm.com>
To: linux-arm-kernel@lists.infradead.org,
	suzuki.poulose@arm.com
Cc: Anshuman Khandual <anshuman.khandual@arm.com>,
	Lorenzo Pieralisi <lpieralisi@kernel.org>,
	Sudeep Holla <sudeep.holla@arm.com>,
	Mike Leach <mike.leach@linaro.org>,
	James Clark <james.clark@arm.com>,
	Maxime Coquelin <mcoquelin.stm32@gmail.com>,
	Alexandre Torgue <alexandre.torgue@foss.st.com>,
	linux-acpi@vger.kernel.org,
	linux-kernel@vger.kernel.org,
	coresight@lists.linaro.org,
	linux-stm32@st-md-mailman.stormreply.com,
	Hanjun Guo <guohanjun@huawei.com>,
	"Rafael J. Wysocki" <rafael@kernel.org>,
	Len Brown <lenb@kernel.org>,
	Leo Yan <leo.yan@linaro.org>
Subject: [PATCH V7 01/11] coresight: etm4x: Fix unbalanced pm_runtime_enable()
Date: Thu, 14 Mar 2024 11:28:33 +0530
Message-Id: <20240314055843.2625883-2-anshuman.khandual@arm.com>
In-Reply-To: <20240314055843.2625883-1-anshuman.khandual@arm.com>
References: <20240314055843.2625883-1-anshuman.khandual@arm.com>
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There is an unbalanced pm_runtime_enable() in etm4_probe_platform_dev()
when etm4_probe() fails. This problem can be observed via the coresight
etm4 module's (load -> unload -> load) sequence when etm4_probe() fails
in etm4_probe_platform_dev().

[   63.379943] coresight-etm4x 7040000.etm: Unbalanced pm_runtime_enable!
[   63.393630] coresight-etm4x 7140000.etm: Unbalanced pm_runtime_enable!
[   63.407455] coresight-etm4x 7240000.etm: Unbalanced pm_runtime_enable!
[   63.420983] coresight-etm4x 7340000.etm: Unbalanced pm_runtime_enable!
[   63.420999] coresight-etm4x 7440000.etm: Unbalanced pm_runtime_enable!
[   63.441209] coresight-etm4x 7540000.etm: Unbalanced pm_runtime_enable!
[   63.454689] coresight-etm4x 7640000.etm: Unbalanced pm_runtime_enable!
[   63.474982] coresight-etm4x 7740000.etm: Unbalanced pm_runtime_enable!

This fixes the above problem - with an explicit pm_runtime_disable() call
when etm4_probe() fails during etm4_probe_platform_dev().

Cc: Lorenzo Pieralisi <lpieralisi@kernel.org>
Cc: Hanjun Guo <guohanjun@huawei.com>
Cc: Sudeep Holla <sudeep.holla@arm.com>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: Len Brown <lenb@kernel.org>
Cc: Suzuki K Poulose <suzuki.poulose@arm.com>
Cc: Mike Leach <mike.leach@linaro.org>
Cc: James Clark <james.clark@arm.com>
Cc: Leo Yan <leo.yan@linaro.org>
Cc: linux-acpi@vger.kernel.org
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-kernel@vger.kernel.org
Cc: coresight@lists.linaro.org
Fixes: 5214b563588e ("coresight: etm4x: Add support for sysreg only devices")
Reviewed-by: James Clark <james.clark@arm.com>
Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
---
 drivers/hwtracing/coresight/coresight-etm4x-core.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/hwtracing/coresight/coresight-etm4x-core.c b/drivers/hwtracing/coresight/coresight-etm4x-core.c
index c2ca4a02dfce..06a9b94b8c13 100644
--- a/drivers/hwtracing/coresight/coresight-etm4x-core.c
+++ b/drivers/hwtracing/coresight/coresight-etm4x-core.c
@@ -2213,6 +2213,9 @@ static int etm4_probe_platform_dev(struct platform_device *pdev)
 	ret = etm4_probe(&pdev->dev);
 
 	pm_runtime_put(&pdev->dev);
+	if (ret)
+		pm_runtime_disable(&pdev->dev);
+
 	return ret;
 }
 
-- 
2.25.1