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-rw-r--r--nixos/modules/kernel-patches/0096-cpuidle-mvebu-indicate-failure-to-enter-deeper-sleep.patch46
1 files changed, 46 insertions, 0 deletions
diff --git a/nixos/modules/kernel-patches/0096-cpuidle-mvebu-indicate-failure-to-enter-deeper-sleep.patch b/nixos/modules/kernel-patches/0096-cpuidle-mvebu-indicate-failure-to-enter-deeper-sleep.patch
new file mode 100644
index 0000000..cd7cf3a
--- /dev/null
+++ b/nixos/modules/kernel-patches/0096-cpuidle-mvebu-indicate-failure-to-enter-deeper-sleep.patch
@@ -0,0 +1,46 @@
+From a8be83aa342b173df49ca938f49c9cd8f9433643 Mon Sep 17 00:00:00 2001
+From: Russell King <rmk+kernel@arm.linux.org.uk>
+Date: Sat, 3 Oct 2015 09:13:05 +0100
+Subject: [PATCH 96/96] cpuidle: mvebu: indicate failure to enter deeper sleep
+ states
+
+The cpuidle ->enter method expects the return value to be the sleep
+state we entered. Returning negative numbers or other codes is not
+permissible since coupled CPU idle was merged.
+
+At least some of the mvebu_v7_cpu_suspend() implementations return the
+value from cpu_suspend(), which returns zero if the CPU vectors back
+into the kernel via cpu_resume() (the success case), or the non-zero
+return value of the suspend actor, or one (failure cases).
+
+We do not want to be returning the failure case value back to CPU idle
+as that indicates that we successfully entered one of the deeper idle
+states. Always return zero instead, indicating that we slept for the
+shortest amount of time.
+
+Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
+---
+ drivers/cpuidle/cpuidle-mvebu-v7.c | 6 +++++-
+ 1 file changed, 5 insertions(+), 1 deletion(-)
+
+diff --git a/drivers/cpuidle/cpuidle-mvebu-v7.c b/drivers/cpuidle/cpuidle-mvebu-v7.c
+index 01a856971f05..18ded9e7cb34 100644
+--- a/drivers/cpuidle/cpuidle-mvebu-v7.c
++++ b/drivers/cpuidle/cpuidle-mvebu-v7.c
+@@ -39,8 +39,12 @@ static int mvebu_v7_enter_idle(struct cpuidle_device *dev,
+ ret = mvebu_v7_cpu_suspend(deepidle);
+ cpu_pm_exit();
+
++ /*
++ * If we failed to enter the desired state, indicate that we
++ * slept lightly.
++ */
+ if (ret)
+- return ret;
++ return 0;
+
+ return index;
+ }
+--
+2.37.2
+