From: Ricky WU <ricky_wu@realtek.com>
To: Ulf Hansson <ulf.hansson@linaro.org>
Cc: "wenchao.chen@unisoc.com" <wenchao.chen@unisoc.com>,
"ricardo@marliere.net" <ricardo@marliere.net>,
"marex@denx.de" <marex@denx.de>,
"linux-mmc@vger.kernel.org" <linux-mmc@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: RE: [PATCH] mmc: core: resume not check card exist before powerup
Date: Fri, 19 Apr 2024 06:53:16 +0000 [thread overview]
Message-ID: <8b966794f2bb4fda8cc7d3e111bfef70@realtek.com> (raw)
In-Reply-To: CAPDyKFo3dkzDDEU7Lk14zH0td0AP=z2RJQibj8SP6JeUuz=iFA@mail.gmail.com
Soft reminder
If this solution, you still have concert on sd.c.
can we just do this check card flow in mmc host power up call_back?
> > >
> > > _mmc_sd_resume
> > > add get_cd before call powerup, make sure the card exist
> >
> > Please elaborate more on what problem you are trying to solve, the
> > above doesn't make much sense to me, sorry.
> >
> > Yes, the card may be removed while the system is suspended. Then, even
> > if ->get_cd() indicates that there is no card inserted in the
> > SD-card-slot, we may still have the card being registered - and then
> > we need to unregister it.
> > That said, we need to call mmc_power_up() in order to try to
> > communicate with the card again. At least that is what the
> > mmc_rescan() work assumes when it runs the bus_ops->detect() callback
> > at some point later in time.
> >
>
> We saw the power up in a short time from waveform when removing the card,
> So we saw mmc_sd_resume call the power up did not check the card exist.
>
> We think this the short time power up maybe cause OCP if no card exist.
> And this power up we think is unnecessary when no card exist.
>
>
> > >
> > > Signed-off-by: Ricky Wu <ricky_wu@realtek.com>
> > > ---
> > > drivers/mmc/core/sd.c | 3 +++
> > > 1 file changed, 3 insertions(+)
> > >
> > > diff --git a/drivers/mmc/core/sd.c b/drivers/mmc/core/sd.c index
> > > 1c8148cdda50..35e036672cfb 100644
> > > --- a/drivers/mmc/core/sd.c
> > > +++ b/drivers/mmc/core/sd.c
> > > @@ -1750,6 +1750,9 @@ static int _mmc_sd_resume(struct mmc_host
> > *host)
> > > if (!mmc_card_suspended(host->card))
> > > goto out;
> > >
> > > + if (host->ops->get_cd && !host->ops->get_cd(host))
> > > + goto out;
> > > +
> > > mmc_power_up(host, host->card->ocr);
> > > err = mmc_sd_init_card(host, host->card->ocr, host->card);
> > > mmc_card_clr_suspended(host->card);
> > > --
> > > 2.25.1
> > >
> >
> > Kind regards
> > Uffe
next prev parent reply other threads:[~2024-04-19 6:53 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-03-27 2:45 [PATCH] mmc: core: resume not check card exist before powerup Ricky Wu
2024-03-28 12:38 ` Ulf Hansson
2024-03-29 9:03 ` Ricky WU
2024-04-19 6:53 ` Ricky WU [this message]
2024-04-25 16:59 ` Ulf Hansson
2024-04-29 6:56 ` Ricky WU
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