Re: [PATCH] arm: dts: imx6qdl-vicut1.dtsi: Add backlight-isb node

[Krzysztof Kozlowski]

On 26/07/2022 08:30, David Jander wrote:
> On Mon, 25 Jul 2022 22:33:12 +0200
> Krzysztof Kozlowski <krzysztof.kozlowski@xxxxxxxxxx> wrote:
> 
>> On 25/07/2022 14:48, David Jander wrote:
>>> On some older hardware models this is needed. It will do no harm if used
>>> with newer models though.
>>>
>>> Signed-off-by: David Jander <david@xxxxxxxxxxx>
>>> ---
>>>  arch/arm/boot/dts/imx6qdl-vicut1.dtsi | 22 ++++++++++++++++++++++
>>>  1 file changed, 22 insertions(+)
>>>
>>> diff --git a/arch/arm/boot/dts/imx6qdl-vicut1.dtsi b/arch/arm/boot/dts/imx6qdl-vicut1.dtsi
>>> index a1676b5d2980..08d425020088 100644
>>> --- a/arch/arm/boot/dts/imx6qdl-vicut1.dtsi
>>> +++ b/arch/arm/boot/dts/imx6qdl-vicut1.dtsi
>>> @@ -37,6 +37,16 @@ backlight_led: backlight_led {
>>>  		power-supply = <&reg_3v3>;
>>>  	};
>>>  
>>> +	/* only for backwards compatibility with old HW */
>>> +	backlight_isb: backlight_isb {  
>>
>> Node name: backlight-isb
>>
>> I know that other node had underscore, but these are not correct for names.
> 
> I know the names are not correct, but they are in the style of existing node
> names in the same file. Do you want me to change them all, or just this one?
> This change would break existing user-space software though, which is something
> I prefer not to do. Unfortunately both names are relied upon by user-space
> software for almost 10 years now, and changing them will force me to maintain
> off-tree patches that revert these changes.
> I understand the reason for the change though, and if you insist I will do it.

Node names are not ABI, thus any user-space depending on them does it
wrong. Could you link/name which user-space depends on it?

I don't understand why new node is also already a dependency. It's a new
node, there cannot be anything which depends on it before it is being
applied in upstream.


Best regards,
Krzysztof