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From: Jisheng Zhang <Jisheng.Zhang@synaptics.com>
To: Adrian Hunter <adrian.hunter@intel.com>
Cc: Ulf Hansson <ulf.hansson@linaro.org>,
	zhang.chunyan@linaro.org,
	"linux-mmc@vger.kernel.org" <linux-mmc@vger.kernel.org>
Subject: Re: [PATCH] mmc: sdhci: Use Auto CMD Auto Select only when v4_mode is true
Date: Thu, 15 Oct 2020 10:12:07 +0800	[thread overview]
Message-ID: <20201015101207.3a88004e@xhacker.debian> (raw)
In-Reply-To: <2c958ccd-e21f-c660-2259-e7051d95c205@intel.com>

On Wed, 14 Oct 2020 22:44:50 +0300 Adrian Hunter wrote:

>
> 
> + Chunyan
> 
> On 14/10/20 1:32 pm, Jisheng Zhang wrote:
> > Auto CMD Auto Select can only be used when v4_mode is enabled.  
> 
> The SDHCI spec. doesn't seem to say that.  AFAICS it refers only to v4.1 not
> v4 mode.

4.10 defines the "Auto CMD Auto Select" mode, v4 mode bit in SDHCI_HOST_CONTROL2
selects V3 compatible or V4 compatible mode, I think the v4 here includes
v4.0, v4.1 and v4.2, so if we want to use the mode we have to ensure v4_mode
is enabled.

thanks

> 
> >
> > Fixes: 427b6514d095 ("mmc: sdhci: Add Auto CMD Auto Select support")
> > Signed-off-by: Jisheng Zhang <Jisheng.Zhang@synaptics.com>
> > ---
> >  drivers/mmc/host/sdhci.c | 3 ++-
> >  1 file changed, 2 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
> > index 592a55a34b58..5e0ec5df4074 100644
> > --- a/drivers/mmc/host/sdhci.c
> > +++ b/drivers/mmc/host/sdhci.c
> > @@ -1386,7 +1386,8 @@ static inline void sdhci_auto_cmd_select(struct sdhci_host *host,
> >        * Select' is recommended rather than use of 'Auto CMD12
> >        * Enable' or 'Auto CMD23 Enable'.
> >        */
> > -     if (host->version >= SDHCI_SPEC_410 && (use_cmd12 || use_cmd23)) {
> > +     if (host->version >= SDHCI_SPEC_410 && host->v4_mode &&
> > +         (use_cmd12 || use_cmd23)) {
> >               *mode |= SDHCI_TRNS_AUTO_SEL;
> >
> >               ctrl2 = sdhci_readw(host, SDHCI_HOST_CONTROL2);
> >  
> 


  reply	other threads:[~2020-10-15  2:12 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-10-13 11:08 eMMC performance regression caused by 427b6514d0953bf Jisheng Zhang
2020-10-13 12:32 ` Ulf Hansson
2020-10-13 13:23   ` Adrian Hunter
2020-10-14 10:32     ` [PATCH] mmc: sdhci: Use Auto CMD Auto Select only when v4_mode is true Jisheng Zhang
2020-10-14 19:44       ` Adrian Hunter
2020-10-15  2:12         ` Jisheng Zhang [this message]
2020-10-15  2:38           ` Jisheng Zhang
2020-10-15  5:57             ` Adrian Hunter
2020-10-15  6:24               ` Jisheng Zhang
2020-10-15  8:50                 ` Adrian Hunter
2020-10-14 10:42     ` eMMC performance regression caused by 427b6514d0953bf Jisheng Zhang

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