Re: [PATCH v2 1/2] arm64: dts: mediatek: alias all enabled serial ports

Chen-Yu Tsai <[email protected]> Mon, 27 Jul 2026 17:49:10 +0800

Newsgroups	org.kernel.vger.linux-serial,org.infradead.lists.linux-arm-kernel,org.infradead.lists.linux-mediatek,org.kernel.vger.linux-devicetree,org.kernel.vger.linux-kernel
Message-ID	<CAGXv+5EM5P-cY2VW9MXc_iSjwq=QY1-OaV-s6W8wD8YTUvFN0g@mail.gmail.com>

On Mon, Jul 27, 2026 at 3:40 PM Carlo Caione <[email protected]> wrote:
>
> On most MediaTek boards only serial0 is aliased, so the remaining
> enabled uarts get first-free ttyS line numbers from the 8250 core in
> probe order. When the console uart defers on its clocks another uart can
> win line 0: console=ttyS0 then ends up on the wrong port and the boot
> looks like a hang on the serial console, depending on probe order.
>
> Signed-off-by: Carlo Caione <[email protected]>
> ---
>  arch/arm64/boot/dts/mediatek/mt6795-sony-xperia-m5.dts    | 1 +
>  arch/arm64/boot/dts/mediatek/mt7622-rfb1.dts              | 1 +
>  arch/arm64/boot/dts/mediatek/mt7986a-bananapi-bpi-r3.dts  | 2 ++
>  arch/arm64/boot/dts/mediatek/mt7986a-rfb.dts              | 2 ++

>  arch/arm64/boot/dts/mediatek/mt8183-kukui.dtsi            | 1 +
>  arch/arm64/boot/dts/mediatek/mt8192-asurada-hayato-r1.dts | 4 ++++

These are the only two MediaTek-based Chromebook designs that use
Bluetooth over UART and have a second UART enabled.

Reviewed-by: Chen-Yu Tsai <[email protected]> # kukui & asurada-hayato