pc-ble-driver no scan response

RE: pc-ble-driver no scan response

Mike Tuev R9FT — Tue, 19 Apr 2022 17:04:48 GMT

Hi,

I also have the problems with receiving of scan responses on API V6 S140. in wireshark I can see many of scan requests and scan responses but I can't see them in on_adv_report() (nordic_uart_client example).

But when I use API V5 S132 - all is ok with getting scan responses.

I guess it might be because of this request when using API V6:

#if NRF_SD_BLE_API >= 6
	else {
		err_code = sd_ble_gap_scan_start(m_adapter, NULL, &m_adv_report_buffer);
		if (err_code != NRF_SUCCESS)
		{
			printf("Scan start failed with error code: %d\n", err_code);
			fflush(stdout);
		}
		else
		{
			printf("Scan started\n");
			fflush(stdout);
		}
	}
#endif

It is a chunk from here https://github.com/NordicSemiconductor/pc-ble-driver/blob/master/examples/nordic_uart_client/main.c

More: I am using nrf52840 dongle and I wonder why there is "connectivity_4.1.4_usb_with_s132_5.1.0.hex" which means it uses softdevice S132. But as of this table https://infocenter.nordicsemi.com/topic/ug_gsg_ses/UG/gsg/softdevices.html S132 is not for nrf52840. And more, nrf52832 doesn't have USB.

May be some one can give answers.

RE: pc-ble-driver no scan response

PaSch — Thu, 12 Nov 2020 12:50:04 GMT

will this bug be resolved, is currently worked on this?

RE: pc-ble-driver no scan response

Torsten Robitzki — Fri, 20 Sep 2019 09:09:58 GMT

I expected to receive Advertising data and Scan Response data seperatly. And I'm able to receive Scan Response data, _but_: It takes up to minutes to receive a single Scan Response. I think this is really an issue with the SD V6 API, which does not allow for larger latency (which is introduced by using the API over USB).

The reason, why you see Scan Response data might be, because you are using an earlier connectivity firmware, which does not have that problem. (Which is unfortunatelly not an option for me, as I'm require some 5.0 features).

We've decided yesterday to not use the pc-ble-driver in our product. Either we will write something on our own, or see, if other vendory provide something similar.

RE: pc-ble-driver no scan response

Geoffrey — Fri, 20 Sep 2019 08:59:56 GMT

Hello,

I Get it.

Advertising data and scanresponse data are send separately.

They both put in relationship directly by nrf connect on mobile and on pc app by using the mac adress. (that's why thez are displayed quickly)

In pc-ble-driver-py it is not the case. Advertising datas ans scan response datas are receive separatly.

the srdata are received when the adv_type calue is None

    def on_gap_evt_adv_report(self, ble_driver, conn_handle, peer_addr, rssi, adv_type, adv_data):
        dev_name_list = None

        if adv_type is None :
            print 'scanResponse'
            print (adv_data.records)

This is the result of the print of oine of my device.

{<Types.manufacturer_specific_data: 255>: [255, 255, DATAS]}

In the end you have to link these data with your device by using the peer_addr

I hope this will help you to solve your problem

Best Regards

Geoffrey

RE: pc-ble-driver no scan response

Torsten Robitzki — Wed, 18 Sep 2019 16:08:29 GMT

Well, that makes sense. Unfortunatelly, this doesn't solve my problem, as I need advertising response and BLE 5.0 features :-(

RE: pc-ble-driver no scan response

Sigurd — Wed, 18 Sep 2019 16:01:14 GMT

[quote userid="4223" url="~/f/nordic-q-a/50082/pc-ble-driver-no-scan-response/210493"]How is nRF Connect using the connectivity differently than the pc-ble-driver[/quote]

pc-ble-driver has support for SoftDevice API version 2, 3, 5 and 6. nRF Connect for Desktop still uses SoftDevice (API) v3, also for nRF52840. The scanning APIs were changed in SoftDevice v6 so that the scanning needs to be restarted for every received advertising packet. That's the reason why you don't have this issue on API v3.

(Edit: nRF52840 products that are going to be listed with Bluetooth SIG need to use use SD v6 and above, ref this QDID list.)

RE: pc-ble-driver no scan response

Torsten Robitzki — Wed, 18 Sep 2019 15:21:40 GMT

By accident, I've used the nRF Connect "Bluetooth Low Energy" modul, which installed the connectivity firmware version 4.1.1 SoftDevice API version 3. nRF Connect was able to show me the advertising response data very quickly, reproducable.

How is nRF Connect using the connectivity differently than the pc-ble-driver? What could I do to get the same behaviour.

RE: pc-ble-driver no scan response

Sigurd — Thu, 05 Sep 2019 15:18:38 GMT

That sounds like a good idea. Unfortunately, I can’t think of any other ways to mitigate or solve this.

RE: pc-ble-driver no scan response

Torsten Robitzki — Thu, 05 Sep 2019 06:51:09 GMT

Hi Sigurd,

thank you very much for reproducing the behavior. I think your first interpretation sounds resonable. Which on the other hand meens, that this issue is not solvable with the current state of the pc-ble-driver.

Adding some kind of automatic-rescan-switch, which would instruct the connectivity firmware to automatically issue the sd_ble_gap_scan_start() would solve the problem. What do you think? Can you think of other methods to at least mitigate the problem?

RE: pc-ble-driver no scan response

Sigurd — Mon, 26 Aug 2019 09:08:25 GMT

Hi,

I have reproduced the behavior here. I have not fully verified it yet, but I currently think the amount of delay between the BLE_GAP_EVT_ADV_REPORT events until scanning is resumed again with sd_ble_gap_scan_start() might be to root cause of this issue.

RE: pc-ble-driver no scan response

Torsten Robitzki — Fri, 16 Aug 2019 08:33:19 GMT

Hi Jørgen,

where you able to reproduce my measurements with the ble_app_uart example?

best regards,

Torsten

RE: pc-ble-driver no scan response

Torsten Robitzki — Fri, 09 Aug 2019 14:44:59 GMT

Hi Jørgen,

I tried to reproduce this with the ble_app_uart example and the results are quite compareable. I've modified the attached nordic_reproducer.cpp to count the number of scan reports received for every address ending in 0xf3 (which is just my device) and to stop execution once, a scan reponse was received. This small tables shows the number of received advertisments and the time it took to receive a first scan response:

470 0m44.629s
549 >0m51.572s
488 0m46.725s
403 0m38.277s
350 0m33.204s
444 0m41.694s
175 0m17.192s
324 0m31.005s
302 0m28.396s

For the second measurement, during the entire runtime of the program, no scan response was received. The attached no_scan_response_II.log shows the program output during a measurement (182 advertisings received until after 18s, a first scan response was received). no_scan_response_II.pcapng contains a wireshark sniff during this 18s.

I don't expect the pc-ble-library to report every scan response, but if the library would report just every 10th, it would be just a matter of a second to get a valid scan response.

Unfortunatelly, my current product design relies on receiving the scan responses, which works fine for native Windows10 and OS/X. I would like to support pc-ble-driver to be able to use BLE 5.0 features without the need to have OS support on the client side.

devzone.nordicsemi.com/.../no_5F00_scan_5F00_response_5F00_II.pcapng devzone.nordicsemi.com/.../no_5F00_scan_5F00_response_5F00_II.log

RE: pc-ble-driver no scan response

Jørgen Holmefjord — Fri, 09 Aug 2019 10:59:38 GMT

Ok, would be great if you could provide this firmware. You have not seen this issue with other devices/firmwares? Could you for instance test one of the stock examples from the SDK? The ble_app_uart example should for instance use scan response.

RE: pc-ble-driver no scan response

Torsten Robitzki — Fri, 09 Aug 2019 09:55:49 GMT

I test always against a specific device, with the very same firmware (running on a nrf52832; which I could provide). The scan response data of that device contains a complete list of 128 bit service UUIDs (containing one entry) and manufacturer specific data (see no_scan_response.pcapng).

RE: pc-ble-driver no scan response

Jørgen Holmefjord — Fri, 09 Aug 2019 09:08:02 GMT

Sorry for the slow reply, I have been very busy during the summer. I'm checking with the developer if we have any testing or known issues with this.

[quote user="Torsten Robitzki"]I made some measurements and found that in most times (5 out of 9), it takes 40 to 50 seconds to receive a first scan response from a specific address, while in all other times (4 out of 9) it takes 2 to 4.3 seconds to receive a first scan response.[/quote]

Are you testing this against a specific device, or are the 9 tests with different devices? Which kind of devices are you testing with?

RE: pc-ble-driver no scan response

Torsten Robitzki — Tue, 06 Aug 2019 13:03:13 GMT

An other observation is, that according to the attached sniff (no_scan_response.pcapng), my device is responding on the next advertising channel and the response time is way behind T_IFS. But I would expect this to be an Nordic Sniffer issue, as receiving scan responses, just by using the OS/X API works as expected.

RE: pc-ble-driver no scan response

Torsten Robitzki — Tue, 06 Aug 2019 11:40:56 GMT

Now I added some LED toggles into the connectivity firmware. In `ble_gap_evt_adv_report_t_enc()` I toggled different LEDs. One LED is toggled for every call to the function, one LED for every event with the MAC address of my device. And finaly, one LED for every scan response. The toggle schema of the LED is comparable to what I receive on the PC side. So nearly no scan responses are reportet to `ble_gap_evt_adv_report_t_enc()`.

On the calling side of `ble_gap_evt_adv_report_t_enc()`, I made sure, that in `ser_conn_ble_event_encoder()` allocating memory is not causing a problem. `ser_hal_transport_tx_pkt_alloc()` never fails.

So I traveled up the call stack and found that in `ser_conn_ble_event_handle()` events are scheduled onto an application queue (`app_sched_event_put()`). So I moved my LED blinking test code infront of the scheduling. Same pattern here, so no events get lost, due to this scheduling.

Further up the call stack, there is just `nrf_sdh_ble_evts_poll()` which calls `sd_ble_evt_get()` and just calls `ser_conn_ble_event_handle()` indirectly. Moveing the LED blinking test code there, reveals the same results.

So it seems, the Softdevice is sending scan requests, the device is responding with scan responses, but the SD is not reporting the responses. Why is that?

RE: pc-ble-driver no scan response

Torsten Robitzki — Tue, 06 Aug 2019 07:44:28 GMT

While further investigating this, I build the connectivity firmware (debug build) and deployed it onto a PCA10056 (to be able to debug it). With this setup, I receive scan responses once in a while. I made some measurements and found that in most times (5 out of 9), it takes 40 to 50 seconds to receive a first scan response from a specific address, while in all other times (4 out of 9) it takes 2 to 4.3 seconds to receive a first scan response.

The specific address I'm looking at, advertises with an interval of ~110ms (according to the sniffer). The time it takes to receive a first scan response devided by the number of received advertising PDUs (ADV_IND) is roughly 2 times 110ms for all measurements. I would expect ~110ms / 3, as the scanned device advertises on all three advertising channels. And of cause during all periods, there are plenty of scan requests made by the connectivity firmware and scan responses by the device.

In my setup, I had to configure the pc-ble-driver client with a baudrate of 100,000 (not 1,000,000 as in the examples). Could this be some kind of congestion on the USB part? If so, why are advertings priorizes over scan responses?

RE: pc-ble-driver no scan response

Torsten Robitzki — Fri, 02 Aug 2019 08:10:49 GMT

Hi Jørgen,

I hope you are doing well. Are you on vacation?

best regards,

Torsten

RE: pc-ble-driver no scan response

Torsten Robitzki — Fri, 26 Jul 2019 13:17:35 GMT

Interessting my scan response also contains Manufactorer Specific data.

RE: pc-ble-driver no scan response

Geoffrey — Fri, 26 Jul 2019 13:11:19 GMT

Hi,

I've got the same problem. But I see that the data are available only if you set a company Id different from 0xffff. I hope this information will help you to understand or fix this issue.

Best Regards

Geoffrey

RE: pc-ble-driver no scan response

Torsten Robitzki — Fri, 26 Jul 2019 05:47:07 GMT

Hi Jørgen,

have you found the time to look into my little reproducer?

best regards,

Torsten

RE: pc-ble-driver no scan response

Torsten Robitzki — Mon, 22 Jul 2019 13:34:47 GMT

Hi Jørgen,

please find attached a small (200 LOC) reproducer. When sniffing the connection between the PCA10059 and my device (based on an nrf52 / s132) I can see scan requests (originating from the PCA10059) and responses (originating from my device).

Please let me know, if you have any questions or if you need any additional support from me.

best regards,

Torsten

BTW: Takk for looking into this!

devzone.nordicsemi.com/.../nordic_5F00_reproducer.cpp

RE: pc-ble-driver no scan response

Torsten Robitzki — Mon, 22 Jul 2019 12:51:16 GMT

Yes, I'm using https://github.com/NordicSemiconductor/pc-ble-driver/archive/v4.1.1.zip and yes, I'm activating scanning (see the attached sniff).

This is part of a larger project, with several dependencies. I will try to strip it down to a bare minimum to provide you with an easy to build example.

RE: pc-ble-driver no scan response

Jørgen Holmefjord — Mon, 22 Jul 2019 12:47:15 GMT

Hi,

Are you using the latest stable version of pc-ble-driver (v4.1.1)? Did you set active scanning in the scan parameters?

If this does not help, can you post the application that you use?

Best regards,
Jørgen