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authorStephen Boyd <sboyd@codeaurora.org>2012-07-02 19:21:06 -0700
committerMark Brown <broonie@opensource.wolfsonmicro.com>2012-07-03 20:25:58 +0100
commitd92d95b6bf2722ffa0fefa7651c51bf336743dd7 (patch)
tree61177e0b126a1a467b6a9fd219fe6e48d74ea76a
parent6887a4131da3adaab011613776d865f4bcfb5678 (diff)
downloadop-kernel-dev-d92d95b6bf2722ffa0fefa7651c51bf336743dd7.zip
op-kernel-dev-d92d95b6bf2722ffa0fefa7651c51bf336743dd7.tar.gz
regulator: Fix recursive mutex lockdep warning
A recursive lockdep warning occurs if you call regulator_set_optimum_mode() on a regulator with a supply because there is no nesting annotation for the rdev->mutex. To avoid this warning, get the supply's load before locking the regulator's mutex to avoid grabbing the same class of lock twice. ============================================= [ INFO: possible recursive locking detected ] 3.4.0 #3257 Tainted: G W --------------------------------------------- swapper/0/1 is trying to acquire lock: (&rdev->mutex){+.+.+.}, at: [<c036e9e0>] regulator_get_voltage+0x18/0x38 but task is already holding lock: (&rdev->mutex){+.+.+.}, at: [<c036ef38>] regulator_set_optimum_mode+0x24/0x224 other info that might help us debug this: Possible unsafe locking scenario: CPU0 ---- lock(&rdev->mutex); lock(&rdev->mutex); *** DEADLOCK *** May be due to missing lock nesting notation 3 locks held by swapper/0/1: #0: (&__lockdep_no_validate__){......}, at: [<c03dbb48>] __driver_attach+0x40/0x8c #1: (&__lockdep_no_validate__){......}, at: [<c03dbb58>] __driver_attach+0x50/0x8c #2: (&rdev->mutex){+.+.+.}, at: [<c036ef38>] regulator_set_optimum_mode+0x24/0x224 stack backtrace: [<c001521c>] (unwind_backtrace+0x0/0x12c) from [<c00cc4d4>] (validate_chain+0x760/0x1080) [<c00cc4d4>] (validate_chain+0x760/0x1080) from [<c00cd744>] (__lock_acquire+0x950/0xa10) [<c00cd744>] (__lock_acquire+0x950/0xa10) from [<c00cd990>] (lock_acquire+0x18c/0x1e8) [<c00cd990>] (lock_acquire+0x18c/0x1e8) from [<c080c248>] (mutex_lock_nested+0x68/0x3c4) [<c080c248>] (mutex_lock_nested+0x68/0x3c4) from [<c036e9e0>] (regulator_get_voltage+0x18/0x38) [<c036e9e0>] (regulator_get_voltage+0x18/0x38) from [<c036efb8>] (regulator_set_optimum_mode+0xa4/0x224) ... Signed-off-by: Stephen Boyd <sboyd@codeaurora.org> Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
-rw-r--r--drivers/regulator/core.c10
1 files changed, 5 insertions, 5 deletions
diff --git a/drivers/regulator/core.c b/drivers/regulator/core.c
index 09a737c..8b4b382 100644
--- a/drivers/regulator/core.c
+++ b/drivers/regulator/core.c
@@ -2519,9 +2519,12 @@ int regulator_set_optimum_mode(struct regulator *regulator, int uA_load)
{
struct regulator_dev *rdev = regulator->rdev;
struct regulator *consumer;
- int ret, output_uV, input_uV, total_uA_load = 0;
+ int ret, output_uV, input_uV = 0, total_uA_load = 0;
unsigned int mode;
+ if (rdev->supply)
+ input_uV = regulator_get_voltage(rdev->supply);
+
mutex_lock(&rdev->mutex);
/*
@@ -2554,10 +2557,7 @@ int regulator_set_optimum_mode(struct regulator *regulator, int uA_load)
goto out;
}
- /* get input voltage */
- input_uV = 0;
- if (rdev->supply)
- input_uV = regulator_get_voltage(rdev->supply);
+ /* No supply? Use constraint voltage */
if (input_uV <= 0)
input_uV = rdev->constraints->input_uV;
if (input_uV <= 0) {
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