borine

> I think the quirk is unneeded ``` if (btusb_find_altsetting(data, 6)) { data->usb_alt6_packet_flow = true; new_alts = 6; } else if (test_bit(BTUSB_USE_ALT1_FOR_WBS, &data->flags)) { new_alts = 1; } else {...

> D: hci.c:141: USB adjusted SCO MTU: 28: 24 Bluealsa currently uses a fixed packet size of 24 bytes for all mSBC over USB - perhaps that is causing the...

The USB interface alternate setting selection for SCO is made by the kernel `btusb` module, and there is no API that allows userspace to influence this. If the driver is...

OK, so if Alt-1 does not work with the Realtek Linux driver, then I think comparisons with the Windows driver are not valid. Perhaps Realtek supply different firmwares for Windows...

... on the subject of firmware, I can't see a file in `/lib/firmware/rtl_bt/` that matches `rtl8167b`. In fact, I can't see any reference to "8167" in the btrtl driver code....

> `hci0: command 0x0405 tx timeout` command 0x0405 is HCI_OP_CREATE_CONN and is sent to establish an ACL connection - this I think is a different issue to SCO MTU errors...

@pv Many thanks for that info. So now we know 72 bytes is correct for Alt-3. PR #550 will therefore work correctly with Alt-3. @xyzzy42 Please can you try PR...

> Feb 09 08:08:53 rune64 systemd[2283]: Reached target Bluetooth. The messages before this indicate that the headphones are attempting to connect before systemd has completed its startup of all the...

I think echo cancellation is a function that is applied to the stream from the **local** microphone, not the remote bluetooth one. It should be performed by an application that...

A wild guess at a possible cause to test: - what version of AVRCP does the android phone use? I *think* that version 1.4 or later is required for the...