[PATCH] soc: imx: gpcv2: Synchronously suspend MIX domains

[Marek Vasut]

On 10/17/21 9:40 PM, Lucas Stach wrote:
> Am Samstag, dem 16.10.2021 um 23:05 +0200 schrieb Marek Vasut:
>> In case the following power domain sequence happens, iMX8M Mini always hangs:
>>    gpumix:on -> gpu:on -> gpu:off -> gpu:on
>> This is likely due to another quirk of the GPC block. This situation can be
>> prevented by always synchronously powering off both the domain and MIX domain.
>> Make it so. This turns the aforementioned sequence into:
>>    gpumix:on -> gpu:on -> gpu:off -> gpumix:off -> gpumix:on -> gpu:on
>>
> Did you test this with the reset sequence fixed? 2b2f106eb552 (Revert
> "soc: imx: gpcv2: move reset assert after requesting domain power up")
> in Shawns tree.

It is also in next, so yes.

> I don't like that this is slowing down the power-down sequence and I'm
> not sure if it's required for the other domains, or if this is again a
> GPU domain specific issue.

That's why I CCed NXP, they might provide clarification.

> However, if it's fixing a hang that isn't
> solved by the proper reset sequence, I would say better safe than
> sorry, and we can always optimize this later if possible.

I have this feeling we will be optimizing them until we end up keeping 
them on all the time, because of the constant quirks ... I hope I am 
wrong about this.

> Under the assumption that it's required even with the proper reset
> sequence:
> Acked-by: Lucas Stach <l.stach at pengutronix.de>

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