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Date:   Sun, 25 Jul 2021 07:47:14 +0200
From:   =?utf-8?B?TWljaGHFgiBLxJlwaWXFhA==?= <kernel@kempniu.pl>
To:     Marcel Holtmann <marcel@holtmann.org>
Cc:     Pauli Virtanen <pav@iki.fi>,
        linux-bluetooth <linux-bluetooth@vger.kernel.org>,
        Joseph Hwang <josephsih@google.com>,
        Hilda Wu <hildawu@realtek.com>,
        Johan Hedberg <johan.hedberg@gmail.com>,
        Luiz Augusto von Dentz <luiz.dentz@gmail.com>
Subject: Re: [PATCH v2] Bluetooth: btusb: check conditions before enabling
 USB ALT 3 for WBS
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 <b86543908684cc6cd9afaf4de10fac7af1a49665.camel@iki.fi>
 <872F0B33-594E-4BD7-8B75-EA96DE8DBA8F@holtmann.org>
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> > Some USB BT adapters don't satisfy the MTU requirement mentioned in
> > commit e848dbd364ac ("Bluetooth: btusb: Add support USB ALT 3 for WBS")
> > and have ALT 3 setting that produces no/garbled audio. Some adapters
> > with larger MTU were also reported to have problems with ALT 3.
> > 
> > Add a flag and check it and MTU before selecting ALT 3, falling back to
> > ALT 1. Enable the flag for Realtek, restoring the previous behavior for
> > non-Realtek devices.
> > 
> > Tested with USB adapters (mtu<72, no/garbled sound with ALT3, ALT1
> > works) BCM20702A1 0b05:17cb, CSR8510A10 0a12:0001, and (mtu>=72, ALT3
> > works) RTL8761BU 0bda:8771, Intel AX200 8087:0029 (after disabling
> > ALT6). Also got reports for (mtu>=72, ALT 3 reported to produce bad
> > audio) Intel 8087:0a2b.
> > 
> > Signed-off-by: Pauli Virtanen <pav@iki.fi>
> > Fixes: e848dbd364ac ("Bluetooth: btusb: Add support USB ALT 3 for WBS")
> 
> before I will apply this, I need Tested-by or Ack-by people that confirm that this fixes their issues now.

For 8087:0a2b (with broken mSBC audio since e848dbd364ac):

Tested-by: Michał Kępień <kernel@kempniu.pl>

It would be nice to get this into the stable tree as e848dbd364ac got
there in v5.13.3 (as 15407b14e27b) and v5.10.51 (as 05298f1733c6).

Thanks!

-- 
Best regards,
Michał Kępień