linux-kernel - Re: [RFC PATCH] regulator: Fix recursive mutex lockdep warning

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Message-ID: <20150806094329.GQ20873@sirena.org.uk>
Date:	Thu, 6 Aug 2015 10:43:29 +0100
From:	Mark Brown <broonie@...nel.org>
To:	Srinivas Kandagatla <srinivas.kandagatla@...aro.org>
Cc:	Liam Girdwood <lgirdwood@...il.com>, linux-kernel@...r.kernel.org
Subject: Re: [RFC PATCH] regulator: Fix recursive mutex lockdep warning

On Wed, Aug 05, 2015 at 05:02:08PM +0100, Srinivas Kandagatla wrote:
> A recursive lockdep warning occurs if you call regulator_set_voltage()
> on a load switches that are modelled as regulators with a parent supply as
> there is no nesting annotation for the rdev->mutex.
> To avoid this warning, use the unlocked version of the get_voltage().

No, just completely removing the locking is broken - the locking is
there for a reason!  This needs some lockdep dance, either something
like what we have for regmaps with a class per regulator or something
more fancy but whatever's going on just hacking out locking to shut up
warnings from lockdep is clearly not a good idea.

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