Re: [PATCH] mmc: sdhci-pci-gli: increase 1.8V regulator wait

From: Ulf Hansson <ulf.hansson@linaro.org>
To: Ben Chuang <benchuanggli@gmail.com>, dlbeer@gmail.com
Cc: Adrian Hunter <adrian.hunter@intel.com>,
	Ben Chuang <ben.chuang@genesyslogic.com.tw>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	linux-mmc <linux-mmc@vger.kernel.org>
Subject: Re: [PATCH] mmc: sdhci-pci-gli: increase 1.8V regulator wait
Date: Tue, 11 May 2021 12:56:20 +0200	[thread overview]
Message-ID: <CAPDyKFoCrFMyDEo8czEjAUPZMiUDcV3hKcYSAfdmujZPe7R58g@mail.gmail.com> (raw)
In-Reply-To: <20210426073251.7726-1-benchuanggli@gmail.com>

On Mon, 26 Apr 2021 at 09:30, Ben Chuang <benchuanggli@gmail.com> wrote:
>
> Hi Daniel,
>
> > Inserting an SD-card on an Intel NUC10i3FNK4 (which contains a GL9755)
> > results in the message:
> >
> >     mmc0: 1.8V regulator output did not become stable
> >
> > Following this message, some cards work (sometimes), but most cards fail
> > with EILSEQ. This behaviour is observed on Debian 10 running kernel
> > 4.19.188, but also with 5.8.18 and 5.11.15.
>
> Glad to receive your report. Thanks.
>
> >
> > The driver currently waits 5ms after switching on the 1.8V regulator for
> > it to become stable. Increasing this to 10ms gets rid of the warning
> > about stability, but most cards still fail. Increasing it to 20ms gets
> > some cards working (a 32GB Samsung micro SD works, a 128GB ADATA
> > doesn't). At 50ms, the ADATA works most of the time, and at 100ms both
> > cards work reliably.
>
> If it is convenient, can you provide the appearance pictures and product
> links of these two cards? We want to buy them.
>
> >
> > Signed-off-by: Daniel Beer <dlbeer@gmail.com>
> > ---
> >  drivers/mmc/host/sdhci-pci-gli.c | 7 ++++++-
> >  1 file changed, 6 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/mmc/host/sdhci-pci-gli.c b/drivers/mmc/host/sdhci-pci-gli.c
> > index 592d79082f58..061618aa247f 100644
> > --- a/drivers/mmc/host/sdhci-pci-gli.c
> > +++ b/drivers/mmc/host/sdhci-pci-gli.c
> > @@ -627,8 +627,13 @@ static void sdhci_gli_voltage_switch(struct sdhci_host *host)
> >        *
> >        * Wait 5ms after set 1.8V signal enable in Host Control 2 register
> >        * to ensure 1.8V signal enable bit is set by GL9750/GL9755.
> > +      *
> > +      * ...however, the controller in the NUC10i3FNK4 (a 9755) requires
> > +      * slightly longer than 5ms before the control register reports that
> > +      * 1.8V is ready, and far longer still before the card will actually
> > +      * work reliably.
> >        */
> > -     usleep_range(5000, 5500);
> > +     usleep_range(100000, 110000);
>
> Looks good for me.

I consider this as an ack and will add you tag to the commit. Please
tell me if I should change.

[...]

Applied for fixes and by adding the below tags, thanks!

Acked-by: Ben Chuang <benchuanggli@gmail.com>
Fixes: e51df6ce668a ("mmc: host: sdhci-pci: Add Genesys Logic GL975x support")
Cc: stable@vger.kernel.org

Kind regards
Uffe