CONFIG_BT_EXT_ADV and scan timeout - ncs 2.9.0 breaking change

[m5k8]

I'm migrating code from ncs 2.7 to 2.9.

I am using CONFIG_BT_EXT_ADV and scan timeout callback - such timeout requires CONFIG_BT_EXT_ADV:  RE: nRF Connect SDK Scan Timeout

It was working fine. Now it's no more. Scan start returns error, and this error boils down to the following code in function valid_le_scan_param() located in ncs/zephyr/subsys/bluetooth/host/scan.c

	if (IS_ENABLED(CONFIG_BT_PRIVACY) &&
	    param->type == BT_LE_SCAN_TYPE_ACTIVE &&
	    param->timeout != 0) {
		/* This is marked as not supported as a stopgap until the (scan,
		 * adv, init) roles are reworked into proper state machines.
		 *
		 * Having proper state machines is necessary to be able to
		 * suspend all roles that use the (resolvable) private address,
		 * update the RPA and resume them again with the right
		 * parameters.
		 *
		 * Else we lower the privacy of the device as either the RPA
		 * update will fail or the scanner will not use the newly
		 * generated RPA.
		 */
		return false;

As can be seen, timeout != 0 ends in error.

It's new condition, added somewhere between ncs 2.7 and 2.9 and I would call it regression and breaking change.

So, what's the expected path forward?

[Einar Thorsrud]

Hi,

This change was introduced in this pull request, fixing this issue. The change is not a regression, and the API doc was updated in the same commit. However, it is a breaking API change that removes a feature. I suggest implementign scan timeout your self in this case, using a k_timer or delayed work queue item or similar, where you call bt_le_scan_stop().

[m5k8]

Thank you!