Patch "Bluetooth: hci_sync: avoid dup filtering when passive scanning with adv monitor" has been added to the 6.1-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

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

    Bluetooth: hci_sync: avoid dup filtering when passive scanning with adv monitor

to the 6.1-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-hci_sync-avoid-dup-filtering-when-passive-.patch
and it can be found in the queue-6.1 subdirectory.

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



commit 420cd9b7f0546d1c61d9e57e7de89504686a8c15
Author: Anton Khirnov <anton@xxxxxxxxxxx>
Date:   Mon Jul 29 21:58:10 2024 +0200

    Bluetooth: hci_sync: avoid dup filtering when passive scanning with adv monitor
    
    [ Upstream commit b5431dc2803ac159d6d4645ae237d15c3cb252db ]
    
    This restores behaviour (including the comment) from now-removed
    hci_request.c, and also matches existing code for active scanning.
    
    Without this, the duplicates filter is always active when passive
    scanning, which makes it impossible to work with devices that send
    nontrivial dynamic data in their advertisement reports.
    
    Fixes: abfeea476c68 ("Bluetooth: hci_sync: Convert MGMT_OP_START_DISCOVERY")
    Signed-off-by: Anton Khirnov <anton@xxxxxxxxxxx>
    Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@xxxxxxxxx>
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/net/bluetooth/hci_sync.c b/net/bluetooth/hci_sync.c
index 320fc1e6dff2a..3d6a22812b498 100644
--- a/net/bluetooth/hci_sync.c
+++ b/net/bluetooth/hci_sync.c
@@ -2880,6 +2880,20 @@ static int hci_passive_scan_sync(struct hci_dev *hdev)
 	} else if (hci_is_adv_monitoring(hdev)) {
 		window = hdev->le_scan_window_adv_monitor;
 		interval = hdev->le_scan_int_adv_monitor;
+
+		/* Disable duplicates filter when scanning for advertisement
+		 * monitor for the following reasons.
+		 *
+		 * For HW pattern filtering (ex. MSFT), Realtek and Qualcomm
+		 * controllers ignore RSSI_Sampling_Period when the duplicates
+		 * filter is enabled.
+		 *
+		 * For SW pattern filtering, when we're not doing interleaved
+		 * scanning, it is necessary to disable duplicates filter,
+		 * otherwise hosts can only receive one advertisement and it's
+		 * impossible to know if a peer is still in range.
+		 */
+		filter_dups = LE_SCAN_FILTER_DUP_DISABLE;
 	} else {
 		window = hdev->le_scan_window;
 		interval = hdev->le_scan_interval;