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From:   Luiz Augusto von Dentz <luiz.dentz@gmail.com>
Date:   Wed, 23 Dec 2020 13:58:25 -0800
Message-ID: <CABBYNZK1kRCvhXnoMbskTYdoFUCOTSAdfUVqv3yftfp_G3NxFA@mail.gmail.com>
Subject: Re: Default to HW mSBC on capable controllers ?
To:     =?UTF-8?Q?Pali_Roh=C3=A1r?= <pali@kernel.org>
Cc:     Joakim Tjernlund <Joakim.Tjernlund@infinera.com>,
        "linux-bluetooth@vger.kernel.org" <linux-bluetooth@vger.kernel.org>
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Hi Pali, Joakim,

On Wed, Dec 23, 2020 at 7:58 AM Pali Roh=C3=A1r <pali@kernel.org> wrote:
>
> On Wednesday 23 December 2020 15:41:01 Joakim Tjernlund wrote:
> > On Mon, 2020-12-21 at 22:07 +0100, Pali Roh=C3=A1r wrote:
> > > On Friday 18 December 2020 13:32:29 Joakim Tjernlund wrote:
> > > > There seems to be quite a few USB controllers gaining the BTUSB_WID=
EBAND_SPEECH which I guess means HW mSBC
> > >
> > > No, it does not mean mSBC.
> > >
> >
> > I forgot, if BTUSB_WIDEBAND_SPEECH does not mean capable of HW mSBC, wh=
at does it mean?
>
> BTUSB_WIDEBAND_SPEECH flag is just for usb bluetooth adapters. Not for
> UART or SDIO bluetooth adapters.
>
> It is a hint set for some bluetooth adapters which are on kernel
> whitelist that wideband speech support is possible for them.

Actually it is meant indicate to application that BT_PKT_STATUS can be
used which enables the implementation of PLC (Packet Loss
Concealment), Ive been advocating to change it or just remove it
entirely and move it to be queried with BT_PKT_STATUS.

> mSBC is not the only one codec which has wideband support.
>
> Based on current "whitelist" implementation it does not mean adapters
> without this hint are not mSBC capable (e.g. new adapters could not be
> on this list) and also there is a theoretical chance that some with this
> flag are not capable of mSBC. But this is only theoretical and I think
> you can say that BTUSB_WIDEBAND_SPEECH is sufficient for mSBC. But it is
> not necessary condition for mSBC (e.g. because of UART or SDIO adapters
> or adapters which are not whitelist yet).
>
> I hope to see AuriStream support which is also wideband speech codec but
> should work also with some adapters which are not able to provide enough
> bandwidth for mSBC.


--=20
Luiz Augusto von Dentz