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@khirnov.net>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/net/bluetooth/hci_sync.c b/net/bluetooth/hci_sync.c
index 2f26147fdf3c9df4bac238e88b9d7f52cc05f4e0..4e90bd722e7b5ca784fb83e59815578801f7a24e 100644 (file)
--- a/net/bluetooth/hci_sync.c
+++ b/net/bluetooth/hci_sync.c
@@ -2972,6 +2972,20 @@ 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;