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Bluetooth: hci_h5: Disable the hci_suspend_notifier for btrtl devices

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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@intel.com>
Cc: Vasily Khoruzhick <anarsoul@gmail.com>
Cc: Abhishek Pandit-Subedi <abhishekpandit@chromium.org>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
This commit is contained in:
Hans de Goede 2021-06-29 21:59:07 +02:00 committed by Marcel Holtmann
parent 4431531c48
commit b4a46996f1
3 changed files with 14 additions and 3 deletions
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7
drivers/bluetooth/hci_h5.c
View file

@ -916,6 +916,13 @@ out_free:
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);

3
drivers/bluetooth/hci_serdev.c
View file

@ -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);

7
drivers/bluetooth/hci_uart.h
View file

@ -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