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From: "Dr. Rainer Kaluscha" <rainer.kaluscha@web.de>
To: Mark Brown <broonie@opensource.wolfsonmicro.com>
Cc: Kevin Liu <kliu5@marvell.com>,
	linux-pm@vger.kernel.org, linux-mmc@vger.kernel.org,
	Chris Ball <cjb@laptop.org>,
	Marek Szyprowski <m.szyprowski@samsung.com>,
	Rainer Kaluscha <ich@rainer-kaluscha.de>,
	Philip Rakity <prakity@nvidia.com>,
	Zhangfei Gao <zhangfei.gao@gmail.com>,
	Haojian Zhuang <haojian.zhuang@gmail.com>,
	Chao Xie <cxie4@marvell.com>, Kevin Liu <keyuan.liu@gmail.com>
Subject: Re: [PATCH 1/2] regulator: add regulator_is_dummy function
Date: Mon, 07 Jan 2013 13:30:54 +0100	[thread overview]
Message-ID: <50EABFFE.9070908@web.de> (raw)
In-Reply-To: <20130107112527.GD4544@opensource.wolfsonmicro.com>

Am 07.01.2013 12:25, schrieb Mark Brown:
> On Mon, Jan 07, 2013 at 01:38:50PM +0800, Kevin Liu wrote:
>> Introduce a regulator_is_dummy function to check whether the
>> regulator is dummy.
>
> No, we've been through this repeatedly.  Whatever problem you're trying
> to bodge around is going to be a problem with some real physical
> regulators too.

Though I don't know the previous discussion, this seems a different case to me.

The problem is that *only* a dummy regulator is available which refuses to do any regulation at 
all.
So sdhci/mmc should better behave as no regulator was available at all.
This may happen if e.g. in a precompiled kernel of some linux distro regulator support 
(including dummy) is enabled but the machine running that kernel doesn't have a known hardware 
regulator. This results in sdhci/mmc failing to enable the SD card reader though it would work 
well without regulator support in the kernel.

Rainer




  parent reply	other threads:[~2013-01-07 12:30 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-01-07  5:38 [PATCH 1/2] regulator: add regulator_is_dummy function Kevin Liu
2013-01-07  5:38 ` [PATCH 2/2] mmc: sdhci: fix dummy regulator issue Kevin Liu
2013-01-07 11:25 ` [PATCH 1/2] regulator: add regulator_is_dummy function Mark Brown
2013-01-07 11:36   ` Kevin Liu
2013-01-07 13:18     ` Mark Brown
2013-01-07 12:30   ` Dr. Rainer Kaluscha [this message]
2013-01-07 13:22     ` Mark Brown

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