Message-id: <521AAFDF.9090608@samsung.com>
Date: Mon, 26 Aug 2013 10:31:11 +0900
From: Jaehoon Chung <jh80.chung@samsung.com>
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To: Doug Anderson <dianders@chromium.org>
Cc: Jaehoon Chung <jh80.chung@samsung.com>, Chris Ball <cjb@laptop.org>,
        Seungwon Jeon <tgih.jun@samsung.com>,
        James Hogan <james.hogan@imgtec.com>,
        Grant Grundler <grundler@chromium.org>,
        Alim Akhtar <alim.akhtar@samsung.com>,
        Abhilash Kesavan <a.kesavan@samsung.com>,
        Tomasz Figa <tomasz.figa@gmail.com>, Olof Johansson <olof@lixom.net>,
        "linux-mmc@vger.kernel.org" <linux-mmc@vger.kernel.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v6 2/3] mmc: dw_mmc: Honor requests to set the clock to 0
 (turn off clock)
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 <CAD=FV=WrZacm7UUB3-qE=ufwkur_55m0puPNdUaGBYszPw9OdQ@mail.gmail.com>
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Hi Doug,

On 08/24/2013 05:40 AM, Doug Anderson wrote:
> Jaehoon,
> 
> On Fri, Aug 23, 2013 at 6:21 AM, Jaehoon Chung <jh80.chung@samsung.com> wrote:
>> Hi Doug,
>>
>> If the clock-gating is enabled, then maybe it's continuously printed the kernel message for Bus_speed.
> 
> Can you explain?  I don't think dw_mmc has support for clock gating
> right now.  ...or are there some patches that I'm not aware of?  I
> could believe that if you've got some non-upstream clock gating
> patches that these would need to be modified to handle it...  ...but
> unless those are slated to land upstream it seems like I can't take
> them into account, can I?
If i enabled the CONFIG_MMC_CLK_GATE, the i have found the below message whenever some operation is run.
I will test more with your patch.

[    6.335000] mmc_host mmc1: Bus speed (slot 0) = 100000000Hz (slot req 52000000Hz, actual 50000000HZ div = 1)
[    6.345000] mmc_host mmc1: Bus speed (slot 0) = 100000000Hz (slot req 52000000Hz, actual 50000000HZ div = 1)
[    6.355000] mmc_host mmc1: Bus speed (slot 0) = 100000000Hz (slot req 52000000Hz, actual 50000000HZ div = 1)
[    6.365000] mmc_host mmc1: Bus speed (slot 0) = 100000000Hz (slot req 52000000Hz, actual 50000000HZ div = 1)
[    6.375000] mmc_host mmc1: Bus speed (slot 0) = 100000000Hz (slot req 52000000Hz, actual 50000000HZ div = 1)
[    6.480000] mmc_host mmc1: Bus speed (slot 0) = 100000000Hz (slot req 52000000Hz, actual 50000000HZ div = 1)
[    6.490000] mmc_host mmc1: Bus speed (slot 0) = 100000000Hz (slot req 52000000Hz, actual 50000000HZ div = 1)
[    6.500000] mmc_host mmc1: Bus speed (slot 0) = 100000000Hz (slot req 52000000Hz, actual 50000000HZ div = 1)
[    6.530000] mmc_host mmc1: Bus speed (slot 0) = 100000000Hz (slot req 52000000Hz, actual 50000000HZ div = 1)
[    6.535000] mmc_host mmc1: Bus speed (slot 0) = 100000000Hz (slot req 52000000Hz, actual 50000000HZ div = 1)
[    6.545000] mmc_host mmc1: Bus speed (slot 0) = 100000000Hz (slot req 52000000Hz, actual 50000000HZ div = 1)

Best Regards,
Jaehoon Chung
> 
> Thanks!
> 
> -Doug
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