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From: Ulf Hansson <ulf.hansson@linaro.org>
Date: Tue, 28 Mar 2017 11:59:48 +0200
Message-ID: <CAPDyKFo=DwzUqFZzh0tcRiYg6GagL8VrXwpd6PyfdZ+qkYgXqw@mail.gmail.com>
Subject: Re: [PATCH] mmc: core: Do not hold re-tuning during CMD6 commands
To: Adrian Hunter <adrian.hunter@intel.com>
Cc: Chaotian Jing <chaotian.jing@mediatek.com>,
        Matthias Brugger <matthias.bgg@gmail.com>,
        Jaehoon Chung <jh80.chung@samsung.com>,
        Shawn Lin <shawn.lin@rock-chips.com>,
        Masahiro Yamada <yamada.masahiro@socionext.com>,
        "linux-mmc@vger.kernel.org" <linux-mmc@vger.kernel.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        "linux-arm-kernel@lists.infradead.org" 
        <linux-arm-kernel@lists.infradead.org>,
        linux-mediatek@lists.infradead.org,
        srv_heupstream <srv_heupstream@mediatek.com>
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[...]

>> The retry mechanism provided by mmc_wait_for_cmd() and friends really only
>> makes sense for simple commands.  In other cases, like this, we need to
>> consider what state the card is in.  For __mmc_switch we need to consider
>> whether the card is busy or whether a timing change been made.
>
> I definitely agree. We should remove retries for CMD6 and perhaps also
> for some other cases.
>
> When we have changed the above in __mmc_switch(), the change Chaotian
> suggest gets a different impact, as it would potentially allow a
> re-tuning to happen before the next CMD1to poll for busy or to check

/s/CMD1/CMD13

> the switch status. This isn't okay.
>
> This all sounds to me that Chaotian's issue may not all be related to
> tuning, but to the CMD6 switch sequence itself. However I may be wrong
> - of course. :-)
>
> [...]
>
> Kind regards
> Uffe