Re: [PATCH v2 2/3] arm64: dts: rockchip: Fix vdec register blocks order on RK3576

From: Krzysztof Kozlowski <krzk@kernel.org>
To: Nicolas Dufresne <nicolas.dufresne@collabora.com>,
	Cristian Ciocaltea <cristian.ciocaltea@collabora.com>
Cc: Rob Herring <robh@kernel.org>,
	Krzysztof Kozlowski <krzk+dt@kernel.org>,
	Conor Dooley <conor+dt@kernel.org>,
	Heiko Stuebner <heiko@sntech.de>,
	Detlev Casanova <detlev.casanova@collabora.com>,
	Ezequiel Garcia <ezequiel@vanguardiasur.com.ar>,
	Mauro Carvalho Chehab <mchehab@kernel.org>,
	Hans Verkuil <hverkuil@kernel.org>,
	kernel@collabora.com, devicetree@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org,
	linux-rockchip@lists.infradead.org, linux-kernel@vger.kernel.org,
	Conor Dooley <conor.dooley@microchip.com>,
	linux-media@vger.kernel.org
Subject: Re: [PATCH v2 2/3] arm64: dts: rockchip: Fix vdec register blocks order on RK3576
Date: Tue, 24 Feb 2026 14:20:25 +0100	[thread overview]
Message-ID: <37bebecf-3e16-446e-907a-d006e4cec4c4@kernel.org> (raw)
In-Reply-To: <366daf706b5dc3942e3340f29151ece1f49460e0.camel@collabora.com>

On 24/02/2026 14:17, Nicolas Dufresne wrote:
> Hi,
> 
> Le mardi 24 février 2026 à 08:22 +0100, Krzysztof Kozlowski a écrit :
>> On Mon, Feb 23, 2026 at 09:49:50PM +0200, Cristian Ciocaltea wrote:
>>> When building device trees for the RK3576 based boards, DTC shows the
>>> following complaint:
>>>
>>>   rk3576.dtsi:1282.30-1304.5: Warning (simple_bus_reg): /soc/video-codec@27b00000: simple-bus unit address format error, expected "27b00100"
>>
>> So you need to fix the unit address. This is what the warning tells you.
> 
> The unit address is where the register range starts. Picking a random point
> inside the range is just bad idea.

Of course and that's why you run tools BEFORE you send patches to tell
you that.

> For anyone that uses spec to develop these
> drivers and device tree, its just plain difficult and error prone.
> 
>>
>>>
>>> Provide the register blocks in the expected address-based order.
>>>
>>> Fixes: da0de806d8b4 ("arm64: dts: rockchip: Add the vdpu383 Video Decoder on rk3576")
>>> Signed-off-by: Cristian Ciocaltea <cristian.ciocaltea@collabora.com>
>>> ---
>>>  arch/arm64/boot/dts/rockchip/rk3576.dtsi | 6 +++---
>>>  1 file changed, 3 insertions(+), 3 deletions(-)
>>>
>>> diff --git a/arch/arm64/boot/dts/rockchip/rk3576.dtsi b/arch/arm64/boot/dts/rockchip/rk3576.dtsi
>>> index 49ccdf12ef7e..45eb0d053a6f 100644
>>> --- a/arch/arm64/boot/dts/rockchip/rk3576.dtsi
>>> +++ b/arch/arm64/boot/dts/rockchip/rk3576.dtsi
>>> @@ -1281,10 +1281,10 @@ gpu: gpu@27800000 {
>>>  
>>>  		vdec: video-codec@27b00000 {
>>>  			compatible = "rockchip,rk3576-vdec";
>>> -			reg = <0x0 0x27b00100 0x0 0x500>,
>>> -			      <0x0 0x27b00000 0x0 0x100>,
>>> +			reg = <0x0 0x27b00000 0x0 0x100>,
>>> +			      <0x0 0x27b00100 0x0 0x500>,
>>>  			      <0x0 0x27b00600 0x0 0x100>;
>>
>> The main block, so probably the lowest address as in unit address,
>> should be used, but this ship has sailed. You shipped this DTS, because
>> the order of items is FIXED. Your binding change is clearly incorrect
>> and ABI break without explanation and without reason, so you cannot use
>> such as an argument here.
> 
> Its not released yet.

Nothing in commit msg explained that and your previous comment about
binding was false. Binding WAS released.

I am not going to check every claim you make whether it is true or not.

Best regards,
Krzysztof