On 09/03/2024 16:43, Biju Das wrote:
> Hi Krzysztof Kozlowski,
>
>> -----Original Message-----
>> From: Krzysztof Kozlowski <krzysztof.kozlowski@xxxxxxxxxx>
>> Sent: Saturday, March 9, 2024 1:30 PM
>> Subject: Re: [PATCH 4/4] arm64: dts: renesas: r9a07g0{43,44,54}: Update usbhs family compatible
>>
>> On 09/03/2024 13:32, Biju Das wrote:
>>> Hi Krzysztof Kozlowski,
>>>
>>>> -----Original Message-----
>>>> From: Krzysztof Kozlowski <krzysztof.kozlowski@xxxxxxxxxx>
>>>> Sent: Saturday, March 9, 2024 12:26 PM
>>>> Subject: Re: [PATCH 4/4] arm64: dts: renesas: r9a07g0{43,44,54}:
>>>> Update usbhs family compatible
>>>>
>>>> On 09/03/2024 13:14, Biju Das wrote:
>>>>> Hi Krzysztof Kozlowski,
>>>>>
>>>>> Thanks for the feedback.
>>>>>
>>>>>> -----Original Message-----
>>>>>> From: Krzysztof Kozlowski <krzysztof.kozlowski@xxxxxxxxxx>
>>>>>> Sent: Saturday, March 9, 2024 12:08 PM
>>>>>> Subject: Re: [PATCH 4/4] arm64: dts: renesas: r9a07g0{43,44,54}:
>>>>>> Update usbhs family compatible
>>>>>>
>>>>>> On 08/03/2024 19:09, Biju Das wrote:
>>>>>>> Replace 'renesas,rza2m-usbhs->renesas,rzg2l-usbhs' as family
>>>>>>> compatible for RZ/G2L family SOCs as there is a difference in
>>>>>>> number of pipe buffers compared to RZ/A2M.
>>>>>>>
>>>>>>> Signed-off-by: Biju Das <biju.das.jz@xxxxxxxxxxxxxx>
>>>>>>> ---
>>>>>>> arch/arm64/boot/dts/renesas/r9a07g043.dtsi | 2 +-
>>>>>>> arch/arm64/boot/dts/renesas/r9a07g044.dtsi | 2 +-
>>>>>>> arch/arm64/boot/dts/renesas/r9a07g054.dtsi | 2 +-
>>>>>>> 3 files changed, 3 insertions(+), 3 deletions(-)
>>>>>>>
>>>>>>> diff --git a/arch/arm64/boot/dts/renesas/r9a07g043.dtsi
>>>>>>> b/arch/arm64/boot/dts/renesas/r9a07g043.dtsi
>>>>>>> index 8721f4c9fa0f..766c54b91acc 100644
>>>>>>> --- a/arch/arm64/boot/dts/renesas/r9a07g043.dtsi
>>>>>>> +++ b/arch/arm64/boot/dts/renesas/r9a07g043.dtsi
>>>>>>> @@ -812,7 +812,7 @@ usb2_phy1: usb-phy@11c70200 {
>>>>>>>
>>>>>>> hsusb: usb@11c60000 {
>>>>>>> compatible = "renesas,usbhs-r9a07g043",
>>>>>>> - "renesas,rza2-usbhs";
>>>>>>> + "renesas,rzg2l-usbhs";
>>>>>>
>>>>>> This looks like ABI break and commit msg is quite vague about it.
>>>>>
>>>>> OK, Will update the commit message as driver is taking care of the
>>>>> backward compatibility.
>>>>
>>>> Ah, I was not precise here, you should consider the impact this is on
>>>> DTB used on other kernels. You guys should really stop using
>>>> imprecise/incorrect generic fallbacks and, since it is usually tricky to know which fallback is
>> correct or not, you should stop using them at all.
>>>
>>> There will be driver change to handle SoC specific compatible.
>>>
>>> So ,
>>>
>>> old DTB + old kernel will have 16 pipe buffers old DTB + newer kernel
>>> will have 9 pipe buffers.
>>> New DTB + new kernel will have 9 pipe buffer.
>>
>> You missed new DTB and old kernel. This breaks all users of DTS. That's the entire point of your broken
>> generic compatibles which you did not address.
>
> As per my knowledge, there is no user in RZ/G2L is using new DTB and old kernel.
> So, it is safe.
What do you mean? There can be hundreds of users like this, every
company could fork the kernel but use exported DTS. Or every other
open-source project using exported/packaged DTS repo.
Best regards,
Krzysztof
