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authorSudeep Holla <sudeep.holla@arm.com>2015-01-08 09:29:04 +0300
committerDaniel Lezcano <daniel.lezcano@linaro.org>2015-01-23 17:05:48 +0300
commit194fe6f28e2819d3f50fbed24c3b72f21501dbfa (patch)
treee76c25ad91ead6ba5d1caaf462c5862888fa691c /drivers/cpuidle/cpuidle-big_little.c
parentec6f34e5b552fb0a52e6aae1a5afbbb1605cc6cc (diff)
downloadlinux-194fe6f28e2819d3f50fbed24c3b72f21501dbfa.tar.xz
drivers: cpuidle: Don't initialize big.LITTLE driver if MCPM is unavailable
If big.LITTLE driver is initialized even when MCPM is unavailable, we get the below warning the first time cpu tries to enter deeper C-states. ------------[ cut here ]------------ WARNING: CPU: 4 PID: 0 at kernel/arch/arm/common/mcpm_entry.c:130 mcpm_cpu_suspend+0x6d/0x74() Modules linked in: CPU: 4 PID: 0 Comm: swapper/4 Not tainted 3.19.0-rc3-00007-gaf5a2cb1ad5c-dirty #11 Hardware name: ARM-Versatile Express [<c0013fa5>] (unwind_backtrace) from [<c001084d>] (show_stack+0x11/0x14) [<c001084d>] (show_stack) from [<c04fe7f1>] (dump_stack+0x6d/0x78) [<c04fe7f1>] (dump_stack) from [<c0020645>] (warn_slowpath_common+0x69/0x90) [<c0020645>] (warn_slowpath_common) from [<c00206db>] (warn_slowpath_null+0x17/0x1c) [<c00206db>] (warn_slowpath_null) from [<c001cbdd>] (mcpm_cpu_suspend+0x6d/0x74) [<c001cbdd>] (mcpm_cpu_suspend) from [<c03c6919>] (bl_powerdown_finisher+0x21/0x24) [<c03c6919>] (bl_powerdown_finisher) from [<c001218d>] (cpu_suspend_abort+0x1/0x14) [<c001218d>] (cpu_suspend_abort) from [<00000000>] ( (null)) ---[ end trace d098e3fd00000008 ]--- This patch fixes the issue by checking for the availability of MCPM before initializing the big.LITTLE cpuidle driver Signed-off-by: Sudeep Holla <sudeep.holla@arm.com> Acked-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com> Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com> Cc: Daniel Lezcano <daniel.lezcano@linaro.org> Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net> Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Diffstat (limited to 'drivers/cpuidle/cpuidle-big_little.c')
-rw-r--r--drivers/cpuidle/cpuidle-big_little.c4
1 files changed, 4 insertions, 0 deletions
diff --git a/drivers/cpuidle/cpuidle-big_little.c b/drivers/cpuidle/cpuidle-big_little.c
index e3e225fe6b45..40c34faffe59 100644
--- a/drivers/cpuidle/cpuidle-big_little.c
+++ b/drivers/cpuidle/cpuidle-big_little.c
@@ -182,6 +182,10 @@ static int __init bl_idle_init(void)
*/
if (!of_match_node(compatible_machine_match, root))
return -ENODEV;
+
+ if (!mcpm_is_available())
+ return -EUNATCH;
+
/*
* For now the differentiation between little and big cores
* is based on the part number. A7 cores are considered little