From: Mark Kettenis <mark.kettenis@xs4all.nl>
To: Akihiko Odaki <akihiko.odaki@daynix.com>
Cc: linux-kernel@vger.kernel.org, devicetree@vger.kernel.org,
linux-arm-kernel@lists.infradead.org, asahi@lists.linux.dev,
krzysztof.kozlowski+dt@linaro.org, robh+dt@kernel.org,
alyssa@rosenzweig.io, sven@svenpeter.dev, marcan@marcan.st,
akihiko.odaki@daynix.com
Subject: Re: [PATCH] arch: arm64: dts: apple: Remove stdout-path
Date: Thu, 01 Dec 2022 15:25:15 +0100 [thread overview]
Message-ID: <877czb42wk.fsf@bloch.sibelius.xs4all.nl> (raw)
In-Reply-To: <20221201103651.27807-1-akihiko.odaki@daynix.com> (message from Akihiko Odaki on Thu, 1 Dec 2022 19:36:51 +0900)
> From: Akihiko Odaki <akihiko.odaki@daynix.com>
> Date: Thu, 1 Dec 2022 19:36:51 +0900
>
> u-boot overrides stdout-path so that it points to /chosen/framebuffer
> with some condition.
> > arm: apple: Point stdout-path to framebuffer when keyboard present
> >
> > Unless you have a spare Apple Silicon machine, getting access to
> > the serial port on Apple Silicon machines requires special
> > hardware. Given that most machines come with a built-in screen
> > the framebuffer is likely to be the most convenient output device
> > for most users. While U-Boot will output to both serial and
> > framebuffer, OSes might not. Therefore set stdout-path to point
> > at /chosen/framebuffer when a keyboard is connected to the machine.
> https://github.com/AsahiLinux/u-boot/commit/a609353e82fd757b7635d18ed6a0828fff657d59
>
> Perhaps it made sense to specify serial0 as stdout-path when the
> framebuffer and keyboard support was inmature, but today it is
> preferrable to use /chosen/framebuffer instead of serial0 for the
> console in the most cases as the u-boot change states.
>
> Remove stdout-path to allow the kernel to choose the appropriate
> console. For Linux, it will be VT, which will be eventually backed by
> the framebuffer, if it is enabled. Otherwise, it will fall back to the
> serial.
U-Boot still relies on serial being the default. It will not touch
stdout-out when running under the m1n1 hypervisor for example. The
m1n1 hypervisor emulates the serial port hardware and developers rely
on this quite heavily. Also, U-boot will only switch to the
framebuffer if a keyboard is connected. This is currently disabled in
the builds for Asahi Linux because the type-A USB ports are not
supported yet in U-Boot. But the plan is to fix that eventually.
So as far as I am concerted NAK.
> Signed-off-by: Akihiko Odaki <akihiko.odaki@daynix.com>
> ---
> arch/arm64/boot/dts/apple/t600x-j314-j316.dtsi | 2 --
> arch/arm64/boot/dts/apple/t600x-j375.dtsi | 2 --
> arch/arm64/boot/dts/apple/t8103-jxxx.dtsi | 2 --
> arch/arm64/boot/dts/apple/t8112-jxxx.dtsi | 2 --
> 4 files changed, 8 deletions(-)
>
> diff --git a/arch/arm64/boot/dts/apple/t600x-j314-j316.dtsi b/arch/arm64/boot/dts/apple/t600x-j314-j316.dtsi
> index 5547f5e7ac5a..14b6bf234f82 100644
> --- a/arch/arm64/boot/dts/apple/t600x-j314-j316.dtsi
> +++ b/arch/arm64/boot/dts/apple/t600x-j314-j316.dtsi
> @@ -30,8 +30,6 @@ chosen {
> #size-cells = <2>;
> ranges;
>
> - stdout-path = "serial0";
> -
> framebuffer0: framebuffer@0 {
> compatible = "apple,simple-framebuffer", "simple-framebuffer";
> reg = <0 0 0 0>; /* To be filled by loader */
> diff --git a/arch/arm64/boot/dts/apple/t600x-j375.dtsi b/arch/arm64/boot/dts/apple/t600x-j375.dtsi
> index 7c207b1df949..22e96b436bf2 100644
> --- a/arch/arm64/boot/dts/apple/t600x-j375.dtsi
> +++ b/arch/arm64/boot/dts/apple/t600x-j375.dtsi
> @@ -28,8 +28,6 @@ chosen {
> #size-cells = <2>;
> ranges;
>
> - stdout-path = "serial0";
> -
> framebuffer0: framebuffer@0 {
> compatible = "apple,simple-framebuffer", "simple-framebuffer";
> reg = <0 0 0 0>; /* To be filled by loader */
> diff --git a/arch/arm64/boot/dts/apple/t8103-jxxx.dtsi b/arch/arm64/boot/dts/apple/t8103-jxxx.dtsi
> index 3c5da0e5a41d..d2483f618d44 100644
> --- a/arch/arm64/boot/dts/apple/t8103-jxxx.dtsi
> +++ b/arch/arm64/boot/dts/apple/t8103-jxxx.dtsi
> @@ -27,8 +27,6 @@ chosen {
> #size-cells = <2>;
> ranges;
>
> - stdout-path = "serial0";
> -
> framebuffer0: framebuffer@0 {
> compatible = "apple,simple-framebuffer", "simple-framebuffer";
> reg = <0 0 0 0>; /* To be filled by loader */
> diff --git a/arch/arm64/boot/dts/apple/t8112-jxxx.dtsi b/arch/arm64/boot/dts/apple/t8112-jxxx.dtsi
> index b6b815d93c3e..af4153dcb55d 100644
> --- a/arch/arm64/boot/dts/apple/t8112-jxxx.dtsi
> +++ b/arch/arm64/boot/dts/apple/t8112-jxxx.dtsi
> @@ -22,8 +22,6 @@ chosen {
> #size-cells = <2>;
> ranges;
>
> - stdout-path = "serial0";
> -
> framebuffer0: framebuffer@0 {
> compatible = "apple,simple-framebuffer", "simple-framebuffer";
> reg = <0 0 0 0>; /* To be filled by loader */
> --
> 2.38.1
>
>
>
next prev parent reply other threads:[~2022-12-01 14:25 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-12-01 10:36 [PATCH] arch: arm64: dts: apple: Remove stdout-path Akihiko Odaki
2022-12-01 14:25 ` Mark Kettenis [this message]
2022-12-01 15:19 ` Akihiko Odaki
2022-12-01 15:46 ` Hector Martin
2022-12-01 16:38 ` Akihiko Odaki
2022-12-01 17:46 ` Hector Martin
2022-12-01 18:14 ` Akihiko Odaki
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