The hci_suspend_notifier which was introduced last year, is causing
problems for uart attached btrtl devices. These devices may loose their
firmware and their baudrate setting over a suspend/resume.
Since we don't even know the baudrate after a suspend/resume recovering
from this is tricky. The driver solves this by treating these devices
the same as USB BT HCIs which drop of the bus during suspend.
Specifically the driver:
1. Simply unconditionally turns the device fully off during
system-suspend to save maximum power.
2. Calls device_reprobe() from a workqueue to fully re-init the device
from scratch on system-resume (unregistering the old HCI and
registering a new HCI).
This means that these devices do not benefit from the suspend / resume
handling work done by the hci_suspend_notifier. At best this unnecessarily
adds some time to the suspend/resume time.
But in practice this is actually causing problems:
1. These btrtl devices seem to not like the HCI_OP_WRITE_SCAN_ENABLE(
SCAN_DISABLED) request being send to them when entering the
BT_SUSPEND_CONFIGURE_WAKE state. The same request send on
BT_SUSPEND_DISCONNECT works fine, but the second one send (unnecessarily?)
from the BT_SUSPEND_CONFIGURE_WAKE transition causes the device to hang:
[ 573.497754] PM: suspend entry (s2idle)
[ 573.554615] Filesystems sync: 0.056 seconds
[ 575.837753] Bluetooth: hci0: Timed out waiting for suspend events
[ 575.837801] Bluetooth: hci0: Suspend timeout bit: 4
[ 575.837925] Bluetooth: hci0: Suspend notifier action (3) failed: -110
2. The PM_POST_SUSPEND / BT_RUNNING transition races with the
driver-unbinding done by the device_reprobe() work.
If the hci_suspend_notifier wins the race it is talking to a dead
device leading to the following errors being logged:
[ 598.686060] Bluetooth: hci0: Timed out waiting for suspend events
[ 598.686124] Bluetooth: hci0: Suspend timeout bit: 5
[ 598.686237] Bluetooth: hci0: Suspend notifier action (4) failed: -110
In both cases things still work, but the suspend-notifier is causing
these ugly errors getting logged and ut increase both the suspend- and
the resume-time by 2 seconds.
This commit avoids these problems by disabling the hci_suspend_notifier.
Cc: Luiz Augusto von Dentz <luiz.von.dentz@xxxxxxxxx>
Cc: Vasily Khoruzhick <anarsoul@xxxxxxxxx>
Cc: Abhishek Pandit-Subedi <abhishekpandit@xxxxxxxxxxxx>
Signed-off-by: Hans de Goede <hdegoede@xxxxxxxxxx>
---
Changes in v3:
- Use hu->flags instead of hu->hdev_flags to store the
HCI_UART_NO_SUSPEND_NOTIFIER flag
Changes in v2:
- Use the new HCI_QUIRK_NO_SUSPEND_NOTIFIER quirk, instead of directly
unregistering the notifier from hci_h5.c
---
drivers/bluetooth/hci_h5.c | 7 +++++++
drivers/bluetooth/hci_serdev.c | 3 +++
drivers/bluetooth/hci_uart.h | 7 ++++---
3 files changed, 14 insertions(+), 3 deletions(-)
diff --git a/drivers/bluetooth/hci_h5.c b/drivers/bluetooth/hci_h5.c
index 27e96681d583..c283504ec3b3 100644
--- a/drivers/bluetooth/hci_h5.c
+++ b/drivers/bluetooth/hci_h5.c
@@ -919,6 +919,13 @@ static int h5_btrtl_setup(struct h5 *h5)
static void h5_btrtl_open(struct h5 *h5)
{
+ /*
+ * Since h5_btrtl_resume() does a device_reprobe() the suspend handling
+ * done by the hci_suspend_notifier is not necessary; it actually causes
+ * delays and a bunch of errors to get logged, so disable it.
+ */
+ set_bit(HCI_UART_NO_SUSPEND_NOTIFIER, &h5->hu->flags);
+
/* Devices always start with these fixed parameters */
serdev_device_set_flow_control(h5->hu->serdev, false);
serdev_device_set_parity(h5->hu->serdev, SERDEV_PARITY_EVEN);
diff --git a/drivers/bluetooth/hci_serdev.c b/drivers/bluetooth/hci_serdev.c
index 9e03402ef1b3..3b00d82d36cf 100644
--- a/drivers/bluetooth/hci_serdev.c
+++ b/drivers/bluetooth/hci_serdev.c
@@ -343,6 +343,9 @@ int hci_uart_register_device(struct hci_uart *hu,
hdev->setup = hci_uart_setup;
SET_HCIDEV_DEV(hdev, &hu->serdev->dev);
+ if (test_bit(HCI_UART_NO_SUSPEND_NOTIFIER, &hu->flags))
+ set_bit(HCI_QUIRK_NO_SUSPEND_NOTIFIER, &hdev->quirks);
+
if (test_bit(HCI_UART_RAW_DEVICE, &hu->hdev_flags))
set_bit(HCI_QUIRK_RAW_DEVICE, &hdev->quirks);
diff --git a/drivers/bluetooth/hci_uart.h b/drivers/bluetooth/hci_uart.h
index 4e039d7a16f8..fb4a2d0d8cc8 100644
--- a/drivers/bluetooth/hci_uart.h
+++ b/drivers/bluetooth/hci_uart.h
@@ -86,9 +86,10 @@ struct hci_uart {
};
/* HCI_UART proto flag bits */
-#define HCI_UART_PROTO_SET 0
-#define HCI_UART_REGISTERED 1
-#define HCI_UART_PROTO_READY 2
+#define HCI_UART_PROTO_SET 0
+#define HCI_UART_REGISTERED 1
+#define HCI_UART_PROTO_READY 2
+#define HCI_UART_NO_SUSPEND_NOTIFIER 3
/* TX states */
#define HCI_UART_SENDING 1
--
2.31.1
