linux-kernel - Re: [PATCH 2/2] regulator: Optimise out noop voltage changes

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Message-ID: <c472e9529b53486845cc4c1554b68e7d.squirrel@www.codeaurora.org>
Date:	Fri, 17 Dec 2010 21:50:15 -0800 (PST)
From:	"Saravana Kannan" <skannan@...eaurora.org>
To:	"Mark Brown" <broonie@...nsource.wolfsonmicro.com>
Cc:	"Saravana Kannan" <skannan@...eaurora.org>,
	"Liam Girdwood" <lrg@...mlogic.co.uk>,
	linux-kernel@...r.kernel.org, patches@...nsource.wolfsonmicro.com
Subject: Re: [PATCH 2/2] regulator: Optimise out noop voltage changes

Mark Brown wrote:
>> 2. When I was trying to do the above this Sunday, I also noticed what
>> looks like a bug or at least an unpleasant behavior. A consumer's min_uV
>> and max_uV were being updated (for-next around Dec 12th) before calling
>> the producer's set voltage. So, in the above example, if consumer C
>> comes
>> in and asks for (10 - 15), it will prevent the producer voltage from
>> ever
>> changing again. All of consumer A and B's future requests will result in
>> a
>> failure since min_uV > max_uV when you do the consumer aggregation.
>
> I'm sorry I can't parse this at all.  What is a producer?
>
> If the consumers are all asking for incompatible things there's a system
> integration issue and the consumers need to be sorted out; it's
> difficult for the regulator API to do anything safely while everything
> wants incompatible configurations.

Sorry for the confusing explanation. Like I said, I didn't have access to
the code and I was using terms I had in my head. Anyway, wrote a quick
patch and sent it your way. Think of it more as an RFC to explain my point
-- I'm more than willing to implement it differently if you don't like it.

Thanks,
Saravana
-- 
Sent by an employee of the Qualcomm Innovation Center, Inc.
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum.


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