On Fri, Dec 18, 2020 at 10:23:08PM +0100, Marcel Holtmann wrote:
> Hi Trent,
>
> > When alt mode 6 is not available, fallback to the kernel <= 5.7 behavior
> > of always using alt mode 1.
> >
> > Prior to kernel 5.8, btusb would always use alt mode 1 for WBS (Wide
> > Band Speech aka mSBC aka transparent SCO). In commit baac6276c0a9
> > ("Bluetooth: btusb: handle mSBC audio over USB Endpoints") this
> > was changed to use alt mode 6, which is the recommended mode in the
> > Bluetooth spec (Specifications of the Bluetooth System, v5.0, Vol 4.B
> > §2.2.1). However, many if not most BT USB adapters do not support alt
> > mode 6. In fact, I have been unable to find any which do.
> patch has been applied to bluetooth-next tree.
For easier application to the stable tree(s) this should probably get:
Fixes: baac6276c0a9 ("Bluetooth: btusb: handle mSBC audio over USB Endpoints")
In my testing this indeed fixes mSBC audio with both a Belkin (Broadcom
BCM20702A, 050d:065a) and an Intel Bluetooth (8087:0a2b) adapters.
Tested-By: Sjoerd Simons <sjoerd@xxxxxxxxxxxxx>
Regards,
Sjoerd
