This fixes the tx timeout issue seen while running a stress test on
btnxpuart for couple of hours, such that the interval between two HCI
commands coincide with the power save timeout value of 2 seconds.
Test procedure using bash script:
<load btnxpuart.ko>
hciconfig hci0 up
//Enable Power Save feature
hcitool -i hci0 cmd 3f 23 02 00 00
while (true)
do
hciconfig hci0 leadv
sleep 2
hciconfig hci0 noleadv
sleep 2
done
Error log, after adding few more debug prints:
[ 2206.497227] Bluetooth: btnxpuart_queue_skb(): 01 0A 20 01 00
[ 2206.498239] Bluetooth: hci0: Set UART break: on, status=0
[ 2206.503283] Bluetooth: hci0: btnxpuart_tx_wakeup() tx_work scheduled
[ 2206.503299] Bluetooth: hci0: btnxpuart_tx_work() dequeue: 01 0A 20 01 00
Can't set advertise mode on hci0: Connection timed out (110)
[ 2208.514238] Bluetooth: hci0: command 0x200a tx timeout
When the power save mechanism turns on UART break, and btnxpuart_tx_work()
is scheduled simultaneously, psdata->ps_state is read as PS_STATE_AWAKE,
which prevents the psdata->work from being scheduled, which is responsible
to turn OFF UART break.
This issue is fixed by adding a ps_lock mutex around UART break on/off as
well as around ps_state read/write.
btnxpuart_tx_wakeup() will now read updated ps_state value. If ps_state is
PS_STATE_SLEEP, it will first schedule psdata->work, and then it will
reschedule itself once UART break has been turned off and ps_state is
PS_STATE_AWAKE.
Tested above script for 50,000 iterations and TX timeout error was not
observed anymore.
Signed-off-by: Neeraj Sanjay Kale <neeraj.sanjaykale@xxxxxxx>
---
drivers/bluetooth/btnxpuart.c | 22 +++++++++++++++++++---
1 file changed, 19 insertions(+), 3 deletions(-)
diff --git a/drivers/bluetooth/btnxpuart.c b/drivers/bluetooth/btnxpuart.c
index b7e66b7ac570..a68d10771c99 100644
--- a/drivers/bluetooth/btnxpuart.c
+++ b/drivers/bluetooth/btnxpuart.c
@@ -126,6 +126,7 @@ struct ps_data {
struct hci_dev *hdev;
struct work_struct work;
struct timer_list ps_timer;
+ struct mutex ps_lock;
};
struct wakeup_cmd_payload {
@@ -337,6 +338,7 @@ static void ps_control(struct hci_dev *hdev, u8 ps_state)
!test_bit(BTNXPUART_SERDEV_OPEN, &nxpdev->tx_state))
return;
+ mutex_lock(&psdata->ps_lock);
switch (psdata->cur_h2c_wakeupmode) {
case WAKEUP_METHOD_DTR:
if (ps_state == PS_STATE_AWAKE)
@@ -356,6 +358,8 @@ static void ps_control(struct hci_dev *hdev, u8 ps_state)
}
if (!status)
psdata->ps_state = ps_state;
+ mutex_unlock(&psdata->ps_lock);
+
if (ps_state == PS_STATE_AWAKE)
btnxpuart_tx_wakeup(nxpdev);
}
@@ -391,17 +395,25 @@ static void ps_setup(struct hci_dev *hdev)
psdata->hdev = hdev;
INIT_WORK(&psdata->work, ps_work_func);
+ mutex_init(&psdata->ps_lock);
timer_setup(&psdata->ps_timer, ps_timeout_func, 0);
}
-static void ps_wakeup(struct btnxpuart_dev *nxpdev)
+static bool ps_wakeup(struct btnxpuart_dev *nxpdev)
{
struct ps_data *psdata = &nxpdev->psdata;
+ u8 ps_state;
+
+ mutex_lock(&psdata->ps_lock);
+ ps_state = psdata->ps_state;
+ mutex_unlock(&psdata->ps_lock);
- if (psdata->ps_state != PS_STATE_AWAKE) {
+ if (ps_state != PS_STATE_AWAKE) {
psdata->ps_cmd = PS_CMD_EXIT_PS;
schedule_work(&psdata->work);
+ return true;
}
+ return false;
}
static int send_ps_cmd(struct hci_dev *hdev, void *data)
@@ -1171,7 +1183,6 @@ static struct sk_buff *nxp_dequeue(void *data)
{
struct btnxpuart_dev *nxpdev = (struct btnxpuart_dev *)data;
- ps_wakeup(nxpdev);
ps_start_timer(nxpdev);
return skb_dequeue(&nxpdev->txq);
}
@@ -1186,6 +1197,11 @@ static void btnxpuart_tx_work(struct work_struct *work)
struct sk_buff *skb;
int len;
+ if (ps_wakeup(nxpdev)) {
+ schedule_work(&nxpdev->tx_work);
+ return;
+ }
+
while ((skb = nxp_dequeue(nxpdev))) {
len = serdev_device_write_buf(serdev, skb->data, skb->len);
hdev->stat.byte_tx += len;
--
2.34.1
