Re: [cip-dev] [PATCH 5.10.y-cip 00/22] RZ/{G2L, G2LC, G2UL, G3S, Five, V2L}: Backport MSTOP support

[Claudiu Beznea <claudiu.beznea@tuxon.dev>]

Hi, Pavel,

On 11/24/25 12:10, Pavel Machek wrote:
> Hi!
> 
>>>>>> I'm going to send a PoC patch for the media drivers used by the
>>>>>> RZ/{G2L, G2LC, G2UL, V2L} SoCs in reply to this thread. Please let me
>>>>>> know how do you consider this approach.
>>>>>
>>>>> I'll take a look, but if mainline is happy, likely I'll be happy, too.
>>>>
>>>> In mainline the problem is already fixed by patches 01-11 from this series.
>>>> The PoC patch that I sent is intended for CIP kernels only, and, along with it, all the other drivers
>>>> used by the RZ/{G2L, G2LC, G2UL, G3S, Five, V2L} SoCs will have to be patched with something similar.
>>>
>>>
>>> What to do with Mali driver used in RZ/{G2L, G2LC, V2L} ? Mali driver is used by other vendors as well.
>>> Maybe special handling??
>>
>> DT nodes for the Mali IP on RZ/{G2L, G2LC, V2L} have Renesas compatibles.
>> Taking into account these compatibles, the code could be adjusted to be
>> executed only for the Renesas SoCs.
> 
> Ok, so we have two solutions:
> 
> 1) one requires small changes to unrelated drivers in the tree
> 
> 2) one that is only touching Renesas code, but is not mainline, an is
> not going mainline
> 
> Neither is good. I don't believe there's another possibility?

I don't know another one at the moment, too.

> 
> I'd still like to know how much power this saves, and if we really
> need to have this in 5.10.

I'll ask internal HW team about it and. In parallel, I'll try on my side to
check the exposed board rails to see if there is any diff in terms of power
consumption w/ and w/o this feature.

> 
> It looks to me like 1) is less bad, and we may have to live with it,
> but I'd like to get confirmation from other stakeholders at this
> point.I t may be best discussed at thursday's IRC meeting. (Do you
> want to join? :-) ).

I'll be there.

Thank you,
Claudiu