Hi Anton,
On Mon, Jul 29, 2024 at 5:06 PM Anton Khirnov <anton@xxxxxxxxxxx> wrote:
>
> This restores behaviour (including the comment) from now-removed
> hci_request.c, and also matches existing code for active scanning.
Make sure you add the Fixes tag with the commit hash that introduced
the problem, since we might want to backport this.
> 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.
>
> Signed-off-by: Anton Khirnov <anton@xxxxxxxxxxx>
> ---
> net/bluetooth/hci_sync.c | 14 ++++++++++++++
> 1 file changed, 14 insertions(+)
>
> diff --git a/net/bluetooth/hci_sync.c b/net/bluetooth/hci_sync.c
> index a31d39a821f4..e79cd40bd079 100644
> --- a/net/bluetooth/hci_sync.c
> +++ b/net/bluetooth/hci_sync.c
> @@ -3019,6 +3019,20 @@ 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;
> --
> 2.39.2
>
>
--
Luiz Augusto von Dentz
