Re: [PATCH 1/3] arm64: dts: rockchip: disable display subsystem for Radxa E52C

From: "Heiko Stübner" <heiko@sntech.de>
To: Chukun Pan <amadeus@jmu.edu.cn>
Cc: Chukun Pan <amadeus@jmu.edu.cn>, FUKAUMI Naoki <naoki@radxa.com>,
	Conor Dooley <conor+dt@kernel.org>,
	Krzysztof Kozlowski <krzk+dt@kernel.org>,
	Rob Herring <robh@kernel.org>,
	linux-arm-kernel@lists.infradead.org,
	linux-rockchip@lists.infradead.org, linux-kernel@vger.kernel.org,
	devicetree@vger.kernel.org
Subject: Re: [PATCH 1/3] arm64: dts: rockchip: disable display subsystem for Radxa E52C
Date: Mon, 11 Aug 2025 08:30:19 +0200	[thread overview]
Message-ID: <3125650.687JKscXgg@diego> (raw)
In-Reply-To: <20250810100020.445053-1-amadeus@jmu.edu.cn>

Am Sonntag, 10. August 2025, 12:00:18 Mitteleuropäische Sommerzeit schrieb Chukun Pan:
> The Radxa E52C SBC do not have HDMI output, so disable
> the display subsystem.
> 
> Fixes: 9be4171219b6 ("arm64: dts: rockchip: Add Radxa E52C")
> Signed-off-by: Chukun Pan <amadeus@jmu.edu.cn>

What actual problem does this fix?

For example we also enable on-soc iommus all the time, because they're on
the soc and don't need board-level properties.

The "display-subsystem" without users looks mostly in the same spot.

So I do expect a description of what proplem gets fixed that this needs
to be disabled.

Thanks
Heiko

> ---
>  arch/arm64/boot/dts/rockchip/rk3582-radxa-e52c.dts | 4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/arch/arm64/boot/dts/rockchip/rk3582-radxa-e52c.dts b/arch/arm64/boot/dts/rockchip/rk3582-radxa-e52c.dts
> index e04f21d8c831..3b519be6e1ea 100644
> --- a/arch/arm64/boot/dts/rockchip/rk3582-radxa-e52c.dts
> +++ b/arch/arm64/boot/dts/rockchip/rk3582-radxa-e52c.dts
> @@ -207,6 +207,10 @@ &cpu_l3 {
>  	cpu-supply = <&vdd_cpu_lit_s0>;
>  };
>  
> +&display_subsystem {
> +	status = "disabled";
> +};
> +
>  &i2c0 {
>  	pinctrl-names = "default";
>  	pinctrl-0 = <&i2c0m2_xfer>;
> 