Patch "Bluetooth: Add new HCI_QUIRK_NO_SUSPEND_NOTIFIER quirk" has been added to the 5.10-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    Bluetooth: Add new HCI_QUIRK_NO_SUSPEND_NOTIFIER quirk

to the 5.10-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-add-new-hci_quirk_no_suspend_notifier-quir.patch
and it can be found in the queue-5.10 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit 3f2f713cd144c0e1b4fc441bca7a5264bb4fcd58
Author: Hans de Goede <hdegoede@xxxxxxxxxx>
Date:   Thu Jan 28 17:33:12 2021 +0100

    Bluetooth: Add new HCI_QUIRK_NO_SUSPEND_NOTIFIER quirk
    
    [ Upstream commit 219991e6be7f4a31d471611e265b72f75b2d0538 ]
    
    Some devices, e.g. the RTL8723BS bluetooth part, some USB attached devices,
    completely drop from the bus on a system-suspend. These devices will
    have their driver unbound and rebound on resume (when the dropping of
    the bus gets detected) and will show up as a new HCI after resume.
    
    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 this may also actually cause problems, if the
    code doing the driver unbinding runs after the pm-notifier then the
    hci_suspend_notifier code will try to talk to a device which is now in
    an uninitialized state.
    
    This commit adds a new HCI_QUIRK_NO_SUSPEND_NOTIFIER quirk which allows
    drivers to opt-out of the hci_suspend_notifier when they know beforehand
    that their device will be fully re-initialized / reprobed on resume.
    
    Signed-off-by: Hans de Goede <hdegoede@xxxxxxxxxx>
    Reviewed-by: Abhishek Pandit-Subedi <abhishekpandit@xxxxxxxxxxxx>
    Signed-off-by: Marcel Holtmann <marcel@xxxxxxxxxxxx>
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/include/net/bluetooth/hci.h b/include/net/bluetooth/hci.h
index c8e67042a3b1..6da4b3c5dd55 100644
--- a/include/net/bluetooth/hci.h
+++ b/include/net/bluetooth/hci.h
@@ -238,6 +238,14 @@ enum {
 	 * during the hdev->setup vendor callback.
 	 */
 	HCI_QUIRK_BROKEN_ERR_DATA_REPORTING,
+
+	/*
+	 * When this quirk is set, then the hci_suspend_notifier is not
+	 * registered. This is intended for devices which drop completely
+	 * from the bus on system-suspend and which will show up as a new
+	 * HCI after resume.
+	 */
+	HCI_QUIRK_NO_SUSPEND_NOTIFIER,
 };
 
 /* HCI device flags */
diff --git a/net/bluetooth/hci_core.c b/net/bluetooth/hci_core.c
index 7a2f9559e99a..0152bc6b6796 100644
--- a/net/bluetooth/hci_core.c
+++ b/net/bluetooth/hci_core.c
@@ -3785,10 +3785,12 @@ int hci_register_dev(struct hci_dev *hdev)
 	hci_sock_dev_event(hdev, HCI_DEV_REG);
 	hci_dev_hold(hdev);
 
-	hdev->suspend_notifier.notifier_call = hci_suspend_notifier;
-	error = register_pm_notifier(&hdev->suspend_notifier);
-	if (error)
-		goto err_wqueue;
+	if (!test_bit(HCI_QUIRK_NO_SUSPEND_NOTIFIER, &hdev->quirks)) {
+		hdev->suspend_notifier.notifier_call = hci_suspend_notifier;
+		error = register_pm_notifier(&hdev->suspend_notifier);
+		if (error)
+			goto err_wqueue;
+	}
 
 	queue_work(hdev->req_workqueue, &hdev->power_on);
 
@@ -3823,9 +3825,11 @@ void hci_unregister_dev(struct hci_dev *hdev)
 
 	cancel_work_sync(&hdev->power_on);
 
-	hci_suspend_clear_tasks(hdev);
-	unregister_pm_notifier(&hdev->suspend_notifier);
-	cancel_work_sync(&hdev->suspend_prepare);
+	if (!test_bit(HCI_QUIRK_NO_SUSPEND_NOTIFIER, &hdev->quirks)) {
+		hci_suspend_clear_tasks(hdev);
+		unregister_pm_notifier(&hdev->suspend_notifier);
+		cancel_work_sync(&hdev->suspend_prepare);
+	}
 
 	hci_dev_do_close(hdev);