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Message-ID: <1490754475.22814.43.camel@mhfsdcap03>
Date: Wed, 29 Mar 2017 10:27:55 +0800
From: Chaotian Jing <chaotian.jing@...iatek.com>
To: Ulf Hansson <ulf.hansson@...aro.org>
CC: Adrian Hunter <adrian.hunter@...el.com>,
Matthias Brugger <matthias.bgg@...il.com>,
Jaehoon Chung <jh80.chung@...sung.com>,
Shawn Lin <shawn.lin@...k-chips.com>,
Masahiro Yamada <yamada.masahiro@...ionext.com>,
"linux-mmc@...r.kernel.org" <linux-mmc@...r.kernel.org>,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
"linux-arm-kernel@...ts.infradead.org"
<linux-arm-kernel@...ts.infradead.org>,
<linux-mediatek@...ts.infradead.org>,
srv_heupstream <srv_heupstream@...iatek.com>
Subject: Re: [PATCH] mmc: core: Do not hold re-tuning during CMD6 commands
On Tue, 2017-03-28 at 11:59 +0200, Ulf Hansson wrote:
> [...]
>
> >> 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.
> >
just only remove retries ? how to do error handle of CMD6 response CRC
error ?
> > 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. :-)
We had already noticed this issue and do busy check before CMD6 was sent
in our host driver. so that for me, the rest work is to do re-tune
before the next cmd6...
> >
> > [...]
> >
> > Kind regards
> > Uffe
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