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FAILED: patch "[PATCH] ARM: cpuidle: Don't register the driver when back-end init" failed to apply to 4.18-stable tree

PATCH [email protected] 1 participant 1 message Nov 19, 2018

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Stable branch CPU idle time management framework
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The patch below does not apply to the 4.18-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

Quoted 1 line

From 763f191af51f127cf8e69cd361f50bf6180768a5 Mon Sep 17 00:00:00 2001

From: Ulf Hansson <[email protected]>
Date: Thu, 1 Nov 2018 13:22:38 +0100
Subject: [PATCH] ARM: cpuidle: Don't register the driver when back-end init
returns -ENXIO

There's no point to register the cpuidle driver for the current CPU, when the initialization of the arch specific back-end data fails by returning -ENXIO.

Instead, let's re-order the sequence to its original flow, by first trying to initialize the back-end part and then act accordingly on the returned error code. Additionally, let's print the error message, no matter of what error code that was returned.

Fixes a0d46a3dfdc3 (ARM: cpuidle: Register per cpuidle device)
Signed-off-by Ulf Hansson <[email protected]>
Reviewed-by Daniel Lezcano <[email protected]>
Cc 4.19+ <[email protected]> # v4.19+
Signed-off-by Rafael J. Wysocki <[email protected]>
drivers/cpuidle/cpuidle-arm.c +10 -12
index 073557f433eb..df564d783216 100644
@@ -103,13 +103,6 @@ static int __init arm_idle_init_cpu(int cpu)
 		goto out_kfree_drv;
 	}
 
-	ret = cpuidle_register_driver(drv);
-	if (ret) {
-		if (ret != -EBUSY)
-			pr_err("Failed to register cpuidle driver\n");
-		goto out_kfree_drv;
-	}
-
 	/*
 	 * Call arch CPU operations in order to initialize
 	 * idle states suspend back-end specific data

@@ -117,15 +110,20 @@ static int __init arm_idle_init_cpu(int cpu)
 	ret = arm_cpuidle_init(cpu);
 
 	/*
-	 * Skip the cpuidle device initialization if the reported
+	 * Allow the initialization to continue for other CPUs, if the reported
 	 * failure is a HW misconfiguration/breakage (-ENXIO).
 	 */
-	if (ret == -ENXIO)
-		return 0;
-
 	if (ret) {
 		pr_err("CPU %d failed to init idle CPU ops\n", cpu);
-		goto out_unregister_drv;
+		ret = ret == -ENXIO ? 0 : ret;
+		goto out_kfree_drv;
+	}
+
+	ret = cpuidle_register_driver(drv);
+	if (ret) {
+		if (ret != -EBUSY)
+			pr_err("Failed to register cpuidle driver\n");
+		goto out_kfree_drv;
 	}
 
 	dev = kzalloc(sizeof(*dev), GFP_KERNEL);