msm: bam_dmux: fix smsm callback racecondition
On targets where the modem can boot first, it is possible for the smsm
callback to be triggered multiple times for the same event as bam_dmux
checks the smsm state asynchronously after registering the callback to
prevent missed events, but the callback could also be called
synchronously for the same event. To fix, store the last event that was
processed, and if the current event is identical to the last event,
ignore it.
CRs-Fixed: 352600
Change-Id: I5fd84e9f829fbb4e943e38734f9bad75190f3515
Signed-off-by: Jeffrey Hugo <jhugo@codeaurora.org>
diff --git a/arch/arm/mach-msm/bam_dmux.c b/arch/arm/mach-msm/bam_dmux.c
index 1572b82..eba5637 100644
--- a/arch/arm/mach-msm/bam_dmux.c
+++ b/arch/arm/mach-msm/bam_dmux.c
@@ -240,6 +240,7 @@
static int a2_pc_disabled_wakelock_skipped;
static int disconnect_ack;
static LIST_HEAD(bam_other_notify_funcs);
+static DEFINE_MUTEX(smsm_cb_lock);
struct outside_notify_func {
void (*notify)(void *, int, unsigned long);
@@ -2116,10 +2117,20 @@
static void bam_dmux_smsm_cb(void *priv, uint32_t old_state, uint32_t new_state)
{
+ static int last_processed_state;
+
+ mutex_lock(&smsm_cb_lock);
bam_dmux_power_state = new_state & SMSM_A2_POWER_CONTROL ? 1 : 0;
DBG_INC_A2_POWER_CONTROL_IN_CNT();
bam_dmux_log("%s: 0x%08x -> 0x%08x\n", __func__, old_state,
new_state);
+ if (last_processed_state == (new_state & SMSM_A2_POWER_CONTROL)) {
+ bam_dmux_log("%s: already processed this state\n", __func__);
+ mutex_unlock(&smsm_cb_lock);
+ return;
+ }
+
+ last_processed_state = new_state & SMSM_A2_POWER_CONTROL;
if (bam_mux_initialized && new_state & SMSM_A2_POWER_CONTROL) {
bam_dmux_log("%s: reconnect\n", __func__);
@@ -2141,6 +2152,7 @@
bam_dmux_log("%s: bad state change\n", __func__);
pr_err("%s: unsupported state change\n", __func__);
}
+ mutex_unlock(&smsm_cb_lock);
}