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

Commit Message

Anton Khirnov July 29, 2024, 3:55 p.m. UTC

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.

Signed-off-by: Anton Khirnov <[e-mail]>
---
 net/bluetooth/hci_sync.c | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

Comments

Luiz Augusto von Dentz July 29, 2024, 4:18 p.m. UTC | #1

Hi Anton,

On Mon, Jul 29, 2024 at 5:06 PM Anton Khirnov <[e-mail]> 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 <[e-mail]>
> ---
>  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
>
>

[e-mail] July 29, 2024, 4:37 p.m. UTC | #2

This is automated email and please do not reply to this email!

Dear submitter,

Thank you for submitting the patches to the linux bluetooth mailing list.
This is a CI test results with your patch series:
PW Link:https://patchwork.kernel.org/project/bluetooth/list/?series=874636

---Test result---

Test Summary:
CheckPatch                    PASS      0.67 seconds
GitLint                       PASS      0.32 seconds
SubjectPrefix                 PASS      0.13 seconds
BuildKernel                   PASS      29.39 seconds
CheckAllWarning               PASS      31.89 seconds
CheckSparse                   PASS      37.55 seconds
CheckSmatch                   PASS      101.62 seconds
BuildKernel32                 PASS      28.38 seconds
TestRunnerSetup               PASS      521.34 seconds
TestRunner_l2cap-tester       PASS      19.81 seconds
TestRunner_iso-tester         FAIL      37.01 seconds
TestRunner_bnep-tester        PASS      4.83 seconds
TestRunner_mgmt-tester        PASS      115.55 seconds
TestRunner_rfcomm-tester      PASS      7.47 seconds
TestRunner_sco-tester         PASS      14.98 seconds
TestRunner_ioctl-tester       PASS      7.84 seconds
TestRunner_mesh-tester        PASS      7.07 seconds
TestRunner_smp-tester         PASS      6.88 seconds
TestRunner_userchan-tester    PASS      5.03 seconds
IncrementalBuild              PASS      27.52 seconds

Details
##############################
Test: TestRunner_iso-tester - FAIL
Desc: Run iso-tester with test-runner
Output:
Total: 122, Passed: 117 (95.9%), Failed: 1, Not Run: 4

Failed Test Cases
ISO Connect Suspend - Success                        Failed       4.180 seconds


---
Regards,
Linux Bluetooth

Patch

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;