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authorStephen Boyd <sboyd@codeaurora.org>2014-03-06 22:44:40 -0800
committerLinus Walleij <linus.walleij@linaro.org>2014-03-12 15:12:19 +0100
commit3525f5556a1b9e15cb1b796771f2c62deed7aa7a (patch)
tree17ae34a6a46f457801d63d733d5dc1c6bb8d350a /drivers/pinctrl/pinctrl-msm.c
parent3c7d563789241442abfaeb0574ed4f93f8fcdebe (diff)
pinctrl: msm: Silence recursive lockdep warning
If a driver calls enable_irq_wake() on a gpio turned interrupt from the msm pinctrl driver we'll get a lockdep warning like so: ============================================= [ INFO: possible recursive locking detected ] 3.14.0-rc3 #2 Not tainted --------------------------------------------- modprobe/52 is trying to acquire lock: (&irq_desc_lock_class){-.....}, at: [<c026aea0>] __irq_get_desc_lock+0x48/0x88 but task is already holding lock: (&irq_desc_lock_class){-.....}, at: [<c026aea0>] __irq_get_desc_lock+0x48/0x88 other info that might help us debug this: Possible unsafe locking scenario: CPU0 ---- lock(&irq_desc_lock_class); lock(&irq_desc_lock_class); *** DEADLOCK *** May be due to missing lock nesting notation 4 locks held by modprobe/52: #0: (&__lockdep_no_validate__){......}, at: [<c04f2864>] __driver_attach+0x48/0x98 #1: (&__lockdep_no_validate__){......}, at: [<c04f2874>] __driver_attach+0x58/0x98 #2: (&irq_desc_lock_class){-.....}, at: [<c026aea0>] __irq_get_desc_lock+0x48/0x88 #3: (&(&pctrl->lock)->rlock){......}, at: [<c04bb4b8>] msm_gpio_irq_set_wake+0x20/0xa8 Silence it by putting the gpios into their own lock class. Signed-off-by: Stephen Boyd <sboyd@codeaurora.org> Acked-by: Bjorn Andersson <bjorn.andersson@sonymobile.com> Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Diffstat (limited to 'drivers/pinctrl/pinctrl-msm.c')
-rw-r--r--drivers/pinctrl/pinctrl-msm.c7
1 files changed, 7 insertions, 0 deletions
diff --git a/drivers/pinctrl/pinctrl-msm.c b/drivers/pinctrl/pinctrl-msm.c
index 9b6b3a79a809..2df3a48974f3 100644
--- a/drivers/pinctrl/pinctrl-msm.c
+++ b/drivers/pinctrl/pinctrl-msm.c
@@ -884,6 +884,12 @@ static void msm_gpio_irq_handler(unsigned int irq, struct irq_desc *desc)
chained_irq_exit(chip, desc);
}
+/*
+ * This lock class tells lockdep that GPIO irqs are in a different
+ * category than their parents, so it won't report false recursion.
+ */
+static struct lock_class_key gpio_lock_class;
+
static int msm_gpio_init(struct msm_pinctrl *pctrl)
{
struct gpio_chip *chip;
@@ -922,6 +928,7 @@ static int msm_gpio_init(struct msm_pinctrl *pctrl)
for (i = 0; i < chip->ngpio; i++) {
irq = irq_create_mapping(pctrl->domain, i);
+ irq_set_lockdep_class(irq, &gpio_lock_class);
irq_set_chip_and_handler(irq, &msm_gpio_irq_chip, handle_edge_irq);
irq_set_chip_data(irq, pctrl);
}