This is a note to let you know that I've just added the patch titled
Bluetooth: btnxpuart: Resolve TX timeout error in power save stress test
to the 6.6-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
bluetooth-btnxpuart-resolve-tx-timeout-error-in-powe.patch
and it can be found in the queue-6.6 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 9e3cbe604b3c1bf8c4be8aaa9a5afc207ff6072d
Author: Neeraj Sanjay Kale <neeraj.sanjaykale@xxxxxxx>
Date: Wed Dec 27 18:59:27 2023 +0530
Bluetooth: btnxpuart: Resolve TX timeout error in power save stress test
[ Upstream commit e4db90e4eb8d5487098712ffb1048f3fa6d25e98 ]
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:
Bluetooth: btnxpuart_queue_skb(): 01 0A 20 01 00
Bluetooth: hci0: Set UART break: on, status=0
Bluetooth: hci0: btnxpuart_tx_wakeup() tx_work scheduled
Bluetooth: hci0: btnxpuart_tx_work() dequeue: 01 0A 20 01 00
Can't set advertise mode on hci0: Connection timed out (110)
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>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@xxxxxxxxx>
Stable-dep-of: 35237475384a ("Bluetooth: btnxpuart: Fix random crash seen while removing driver")
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/bluetooth/btnxpuart.c b/drivers/bluetooth/btnxpuart.c
index b5d40e0e05f31..2e18f89a931b8 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 {
@@ -333,6 +334,9 @@ static void ps_start_timer(struct btnxpuart_dev *nxpdev)
if (psdata->cur_psmode == PS_MODE_ENABLE)
mod_timer(&psdata->ps_timer, jiffies + msecs_to_jiffies(psdata->h2c_ps_interval));
+
+ if (psdata->ps_state == PS_STATE_AWAKE && psdata->ps_cmd == PS_CMD_ENTER_PS)
+ cancel_work_sync(&psdata->work);
}
static void ps_cancel_timer(struct btnxpuart_dev *nxpdev)
@@ -353,6 +357,7 @@ 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)
@@ -366,12 +371,15 @@ static void ps_control(struct hci_dev *hdev, u8 ps_state)
status = serdev_device_break_ctl(nxpdev->serdev, 0);
else
status = serdev_device_break_ctl(nxpdev->serdev, -1);
+ msleep(20); /* Allow chip to detect UART-break and enter sleep */
bt_dev_dbg(hdev, "Set UART break: %s, status=%d",
str_on_off(ps_state == PS_STATE_SLEEP), status);
break;
}
if (!status)
psdata->ps_state = ps_state;
+ mutex_unlock(&psdata->ps_lock);
+
if (ps_state == PS_STATE_AWAKE)
btnxpuart_tx_wakeup(nxpdev);
}
@@ -407,17 +415,25 @@ 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;
- if (psdata->ps_state != PS_STATE_AWAKE) {
+ mutex_lock(&psdata->ps_lock);
+ ps_state = psdata->ps_state;
+ mutex_unlock(&psdata->ps_lock);
+
+ 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)
@@ -1215,7 +1231,6 @@ 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);
}
@@ -1230,6 +1245,9 @@ static void btnxpuart_tx_work(struct work_struct *work)
struct sk_buff *skb;
int len;
+ if (ps_wakeup(nxpdev))
+ return;
+
while ((skb = nxp_dequeue(nxpdev))) {
len = serdev_device_write_buf(serdev, skb->data, skb->len);
hdev->stat.byte_tx += len;
