Bluetooth: Cannot connect if extended advertising is enabled in prj.conf

[chrisswinchatt-arm]

Describe the bug

A Zephyr program compiled with the following in prj.conf:

CONFIG_BT=y
CONFIG_BT_CENTRAL=y
CONFIG_BT_PERIPHERAL=y
CONFIG_BT_EXT_ADV=y
CONFIG_BT_PER_ADV=y

Calling bt_conn_le_create after discovering a peer returns -5 (-EIO) when compiled with the above config. Removing or setting to n the CONFIG_BT_EXT_ADV option and recompiling corrects the behaviour.

CONFIG_BT_EXT_ADV	CONFIG_BT_PER_ADV	Return value of bt_conn_le_create
n	n	0
n	y	0
y	n	-5
y	y	-5

To Reproduce
Steps to reproduce the behavior:

1. Compile the code in this gist
2. Flash to the boards; I tested with nucleo_wb55rg, disco_l475_iot1 and nrf52840_mdk; which is central and which is peripheral doesn't matter
3. Use serial console to send A to one board to tell it to advertise and S to the other to tell it to scan
4. The error is shown on the serial console of the scanning board when it attempts to connect

Expected behavior
It should be possible for a single program to support both connect & periodic sync.

Impact
Showstopper

Logs and console output

*** Booting Zephyr OS build zephyr-v2.5.0-2959-g9a14f627426b  ***
Initialising...
Press A to start advertising or S to start scanning
Scanning for 10 seconds
Connecting to Issue (80:e1:26:1b:76:02)
bt_conn_le_create: error -5

Environment (please complete the following information):

• OS: (e.g. Linux, MacOS, Windows) Windows
• Toolchain (e.g Zephyr SDK, ...): Zephyr / West
• Commit SHA or Version used: 9a14f62

Additional context
N/A

[chrisswinchatt-arm]

Update: Created a simplified Gist.

Our real program is in C++ but the Gist in C also reproduces the error so C++ support is not responsible.

[joerchan]

Support for extended advertising needs to be enabled in the zephyr controller.
CONFIG_BT_CTLR_ADV_EXT=y

[carlescufi]

@chrisswinchatt-arm if you objective is to come up with a power consumption comparison between different RTOS, may I point out that you need to take into account not only Bluetooth, but also things like other peripherals (the UART in particular) as well as the behavior of the application itself.

[joerchan]

Did some digging because it was weird that only creating connections was affected, but advertising and scanning worked fine.

Turns out the feature bit checking was inconsistent, I've created a fix for it.

[chrisswinchatt-arm]

Thanks for speedy response all.