enable / disable indication issue when characteristic is already sending

RE: enable / disable indication issue when characteristic is already sending

FormerMember — Tue, 08 Mar 2016 15:00:51 GMT

@makouda could you please upload a sniffer trace containing this problem?

RE: enable / disable indication issue when characteristic is already sending

RK — Tue, 08 Mar 2016 13:36:53 GMT

Go and report a bug against the softdevice then because the indication is guaranteed to go out if it's accepted and the peripheral is required to reply to it so the stack is required to tell you the reply has been received and the buffer is free. There isn't even an error code involved, the peripheral replies with the standard response.

Ensure you have a sniffer trace of the connection to accompany your bug report to show what's happening.

RE: enable / disable indication issue when characteristic is already sending

makouda — Tue, 08 Mar 2016 13:14:56 GMT

im waiting for indication event and I can see that it's not called at all. the connection is always established. case BLE_GATTS_EVT_HVC: indication_pending = false; . this flag is set to false if NRF_ERROR_INVALID_STATE is returned on the send function. so the the state is valid

RE: enable / disable indication issue when characteristic is already sending

RK — Tue, 08 Mar 2016 12:34:03 GMT

For the third time, if the indication is accepted by the stack it will go out, if it goes out a reply will come back, when the reply comes back the buffer will be released and the callback will occur. There is no race condition, it doesn't matter if indications are turned off, as long as the link is up the client will reply. This is all in the bluetooth spec.

RE: enable / disable indication issue when characteristic is already sending

makouda — Tue, 08 Mar 2016 12:27:14 GMT

How about in case the indications are on. Then it goes out and then I disable them. The out message is received anyway???

RE: enable / disable indication issue when characteristic is already sending

RK — Tue, 08 Mar 2016 12:17:15 GMT

What you're asking doesn't make any sense. There isn't a lost indication, if indications haven't been turned off by the time you send yours, it goes out and it gets ack'ed. if they have been turned off then you get the invalid state call and it doesn't go out at all.

And most likely that invalid state error is why you 'hang', because you are, as I suggested earlier, ending up in the error handler. You really would do yourself an awful lot of good if you put a breakpoint in your error handler or learned to hit the break button in your debugger, you'd find the cause very much faster.

RE: enable / disable indication issue when characteristic is already sending

makouda — Tue, 08 Mar 2016 11:35:46 GMT

this is what im doing in my code, I check first that indication are enabled on is_flash_data_indication_enabled . when I disable indication on the phone side, is there any event triggered to notify me that last indication is lost, so that I can send another one???

RE: enable / disable indication issue when characteristic is already sending

FormerMember — Tue, 08 Mar 2016 11:33:25 GMT

If you try to send an indication after indications has been disabled, sd_ble_gatts_hvx(..) will return the error NRF_ERROR_INVALID_STATE. You could for example verify if that causes some problems.

Indications (and notifications) can only be enabled and disabled by the client (in this case the central). The reason is the following: when the server (often the peripheral) updates values to the client, the client has to be ready to receive these updates.

RE: enable / disable indication issue when characteristic is already sending

RK — Mon, 07 Mar 2016 23:37:30 GMT

Start with the usual question "whole system hang". Have you put a breakpoint in the error handler or used the debugger to break and find out if you are in the error handler or one of the fault handlers? That's the first thing to do when 'the whole system hang'.