Hi David, On Thu, May 3, 2018 at 7:42 PM David Llewellyn-Jones <david@xxxxxxxxxxxx> wrote: > Hi, > I've been using bluez on a combination of an Ubuntu laptop running bluez > 5.49 compiled from source and a Sailfish OS phone running the default > install bluez 5.47. On the laptop I'm using DBUS to interact with bluez; > on the phone I'm going via the QTBluetoothDiscoveryAgent interface, > running QT 5.6. > The difficulty I've been experiencing is that BLE advertisements sent > from the laptop in peripheral mode aren't being discovered by the phone. > I can see the advertisements being picked up by btmon on the phone, but > it doesn't filter up to the QT wrapper. Looking through the bluez source > code, it appears that the reason is because in the case of unfiltered > discovery, bluez ignores adverts that don't have either EIR_LIM_DISC or > EIR_GEN_DISC flags set, as in the following code: https://git.kernel.org/pub/scm/bluetooth/bluez.git/tree/src/adapter.c?h=5.47#n5658 > However, as far as I can tell (I could easily be wrong), bluez never > adds these flags into the advertising data. I was expecting to see them > added in the following bit of code: https://git.kernel.org/pub/scm/bluetooth/bluez.git/tree/src/shared/ad.c#n423 > As a result, I can't figure out a way to produce advertisements from my > laptop that can be picked up by my phone. > Adding the flags by calling the following function within > bt_ad_generate() with a value of 0x06 fixed the issue (i.e. allowed my > phone to discover my laptop). > static void serialize_flags(uint8_t value, uint8_t *buf, uint8_t *pos) > { > if (value == 0) > return; > buf[(*pos)++] = sizeof(value) + 1; > buf[(*pos)++] = EIR_FLAGS; > buf[(*pos)++] = value; > } > My question is therefore whether there's a way for bluez to produce BLE > advertisements (on my laptop) that can be picked up by a non-filtered > scan using bluez (on my phone). I searched the Web and the list archives > but didn't find anything that seemed to help answer. It is actually added if you have marked the adapter as Discoverable: https://git.kernel.org/pub/scm/bluetooth/bluez.git/tree/src/advertising.c#n740 There has been some debate if we should have this per instance but that would probably require some changes in the way we deal with whitelist devices since currently we only allow unknown devices to connect when discoverable. -- Luiz Augusto von Dentz -- To unsubscribe from this list: send the line "unsubscribe linux-bluetooth" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
