Re: [PATCH] Bluetooth: qca: fix device-address endianness

[Johan Hovold <johan@kernel.org>]

On Tue, Feb 13, 2024 at 03:55:06PM +0000, Matthias Kaehlcke wrote:
> On Tue, Feb 13, 2024 at 03:41:56PM +0100, Johan Hovold wrote:
> > On Wed, Dec 27, 2023 at 07:03:06PM +0100, Johan Hovold wrote:
> > > The WCN6855 firmware on the Lenovo ThinkPad X13s expects the Bluetooth
> > > device address in MSB order when setting it using the
> > > EDL_WRITE_BD_ADDR_OPCODE command.

> > > Reverse the little-endian address before setting it to make sure that
> > > the address can be configured using tools like btmgmt or using the
> > > 'local-bd-address' devicetree property.
> > > 
> > > Note that this can potentially break systems with boot firmware which
> > > has started relying on the broken behaviour and is incorrectly passing
> > > the address via devicetree in MSB order.
> > > 
> > > Fixes: 5c0a1001c8be ("Bluetooth: hci_qca: Add helper to set device address")
> > > Cc: stable@vger.kernel.org      # 5.1
> > > Cc: Balakrishna Godavarthi <quic_bgodavar@quicinc.com>
> > > Cc: Matthias Kaehlcke <mka@chromium.org>
> > > Signed-off-by: Johan Hovold <johan+linaro@kernel.org>
> > 
> > Can we go ahead and merge this one to get this fixed in 6.8?
> > 
> > I've spoken to Bjorn Andersson at Qualcomm about this and he is in
> > favour of doing so. The only people actually using the devicetree
> > property should be the Chromium team and they control their own boot
> > firmware and should be able to update it in lockstep (and Android uses
> > some custom hacks to set the address that are not in mainline).
> 
> Unfortunately it's not as trivial as it sounds for Chrome OS. The boot
> firmware is controlled by Chrome OS, however for any baseboard (e.g.
> 'trogdor') there is a larger number binary firmware packages, one
> for every model derived from that baseboard. There can be dozens of
> models. Chrome OS Firmware releases are qualified and rolled out per
> model. FW qual may involve the ODM, usually there are multiple ODMs
> per board. In an absolute emergency it would be possible to coordinate
> a qual and synced rollout for all models, but it's definitely
> non-trivial in terms of operations.

Ok, fair enough.

Could you please provide a list of the compatible strings that you guys
currently use and I can add new compatible strings for those, while
keeping the current ones for backwards compatibility with older boot
firmware?

Johan