From: Hans Verkuil <hverkuil-cisco@xxxxxxxxx>
commit 713bdfa10b5957053811470d298def9537d9ff13 upstream.
The en/disable_irq() functions keep track of the 'depth': i.e. if
interrupts are disabled twice, then it needs to enable_irq() calls to
enable them again. The cec-pin framework didn't take this into accound
and could disable irqs multiple times, and it expected that a single
enable_irq() would enable them again.
Move all calls to en/disable_irq() to the kthread where it is easy
to keep track of the current irq state and ensure that multiple
en/disable_irq calls never happen.
If interrupts where disabled twice, then they would never turn on
again, leaving the CEC adapter in a dead state.
Signed-off-by: Hans Verkuil <hverkuil-cisco@xxxxxxxxx>
Fixes: 865463fc03ed (media: cec-pin: add error injection support)
Cc: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/media/cec/core/cec-pin.c | 31 ++++++++++++++++++-------------
1 file changed, 18 insertions(+), 13 deletions(-)
--- a/drivers/media/cec/core/cec-pin.c
+++ b/drivers/media/cec/core/cec-pin.c
@@ -1033,6 +1033,7 @@ static int cec_pin_thread_func(void *_ad
{
struct cec_adapter *adap = _adap;
struct cec_pin *pin = adap->pin;
+ bool irq_enabled = false;
for (;;) {
wait_event_interruptible(pin->kthread_waitq,
@@ -1060,6 +1061,7 @@ static int cec_pin_thread_func(void *_ad
ns_to_ktime(pin->work_rx_msg.rx_ts));
msg->len = 0;
}
+
if (pin->work_tx_status) {
unsigned int tx_status = pin->work_tx_status;
@@ -1083,27 +1085,39 @@ static int cec_pin_thread_func(void *_ad
switch (atomic_xchg(&pin->work_irq_change,
CEC_PIN_IRQ_UNCHANGED)) {
case CEC_PIN_IRQ_DISABLE:
- pin->ops->disable_irq(adap);
+ if (irq_enabled) {
+ pin->ops->disable_irq(adap);
+ irq_enabled = false;
+ }
cec_pin_high(pin);
cec_pin_to_idle(pin);
hrtimer_start(&pin->timer, ns_to_ktime(0),
HRTIMER_MODE_REL);
break;
case CEC_PIN_IRQ_ENABLE:
+ if (irq_enabled)
+ break;
pin->enable_irq_failed = !pin->ops->enable_irq(adap);
if (pin->enable_irq_failed) {
cec_pin_to_idle(pin);
hrtimer_start(&pin->timer, ns_to_ktime(0),
HRTIMER_MODE_REL);
+ } else {
+ irq_enabled = true;
}
break;
default:
break;
}
-
if (kthread_should_stop())
break;
}
+ if (pin->ops->disable_irq && irq_enabled)
+ pin->ops->disable_irq(adap);
+ hrtimer_cancel(&pin->timer);
+ cec_pin_read(pin);
+ cec_pin_to_idle(pin);
+ pin->state = CEC_ST_OFF;
return 0;
}
@@ -1130,13 +1144,7 @@ static int cec_pin_adap_enable(struct ce
hrtimer_start(&pin->timer, ns_to_ktime(0),
HRTIMER_MODE_REL);
} else {
- if (pin->ops->disable_irq)
- pin->ops->disable_irq(adap);
- hrtimer_cancel(&pin->timer);
kthread_stop(pin->kthread);
- cec_pin_read(pin);
- cec_pin_to_idle(pin);
- pin->state = CEC_ST_OFF;
}
return 0;
}
@@ -1157,11 +1165,8 @@ void cec_pin_start_timer(struct cec_pin
if (pin->state != CEC_ST_RX_IRQ)
return;
- atomic_set(&pin->work_irq_change, CEC_PIN_IRQ_UNCHANGED);
- pin->ops->disable_irq(pin->adap);
- cec_pin_high(pin);
- cec_pin_to_idle(pin);
- hrtimer_start(&pin->timer, ns_to_ktime(0), HRTIMER_MODE_REL);
+ atomic_set(&pin->work_irq_change, CEC_PIN_IRQ_DISABLE);
+ wake_up_interruptible(&pin->kthread_waitq);
}
static int cec_pin_adap_transmit(struct cec_adapter *adap, u8 attempts,
