linux-kernel - Re: [PATCH AUTOSEL for 4.9 43/50] regulator: core: Don't use regulators as supplies until the parent is bound

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Message-ID: <20171106181943.glzbrt54oyqmamm6@sasha-lappy>
Date:   Mon, 6 Nov 2017 18:19:46 +0000
From:   "Levin, Alexander (Sasha Levin)" <alexander.levin@...izon.com>
To:     Mark Brown <broonie@...nel.org>
CC:     "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "stable@...r.kernel.org" <stable@...r.kernel.org>,
        Jon Hunter <jonathanh@...dia.com>
Subject: Re: [PATCH AUTOSEL for 4.9 43/50] regulator: core: Don't use
 regulators as supplies until the parent is bound

On Wed, Oct 25, 2017 at 10:06:36AM +0200, Mark Brown wrote:
>On Wed, Oct 25, 2017 at 01:56:02AM +0000, Levin, Alexander (Sasha Levin) wrote:
>
>> When regulators are successfully registered, we check to see if the
>> regulator is a supply for any other registered regulator and if so
>> add the new regulator as the supply for the existing regulator(s).
>
>This had some knock on effects which caused trouble for other things,
>for example 3827b64dba (regulator: core: Resolve supplies before
>disabling unused regulators).
>
>In general I would be extremely wary of backporting anything like this
>that affects things like device instantiation ordering, even without any
>knock on bugs directly in the code there's a good chance that someone
>building on stable is going to have some kind of dependency on the
>particular behaviour of the kernel version they're using and changes
>like this could cause updating to the latest stable to introduce
>problems which then discourages people from picking up stable.

On the other hand, we do want to be "bug compatible" with upstream,
if we force a stable release to behave in a broken way it'll be hard
later to move to a newer stable release.

I think that we'd rather pull in fixes than avoid breaking broken
behaviors.

-- 

Thanks,
Sasha