On 2011-04-02, 08:59 +0800, Dong, Chuanxiao wrote:
> >
> > + lastclock = host->iosclock;
> > + host->iosclock = ios->clock;
> > + if (lastclock == 0 && ios->clock != 0) {
> > + spin_unlock_irqrestore(&host->lock, flags);
> > + pm_runtime_get_sync(host->mmc->parent);
> > + spin_lock_irqsave(&host->lock, flags);
> > + } else if (lastclock != 0 && ios->clock == 0) {
> > + spin_unlock_irqrestore(&host->lock, flags);
> > + pm_runtime_mark_last_busy(host->mmc->parent);
> > + pm_runtime_put_autosuspend(host->mmc->parent);
> > + spin_lock_irqsave(&host->lock, flags);
> I saw there is a potential bug when we disabled the runtime pm,
> actually I already saw this bug on MFLD. To my understanding, I
> think we need at least to add "host->pwr = 0;" here. I found on
> MFLD, each time when remove the SD card, the power control register
> of host controller becomes 0x0. So if you doesn't force to clean
> pwr, the next time sdhci_set_power will return with doing
> nothing. This only happened if the runtime pm feature is disabled.
Exactly.
I have concerns to this piece of code too, is it a good ideal to move
it to the end of sdhci_set_ios()? Since I'm worrying about sdhci be
put into suspend and registers are not in the right status...
> > + }
> > + /* no need to configure the rest.. */
> > + if (host->iosclock == 0)
> > + goto out;
> > +
This is wrong, we can not directly return here.
We're already suffering from this:
https://bugs.meego.com/show_bug.cgi?id=19251
From: "Yin, Kangkai" <[email protected]>
We should not go out when iosclock == 0, if we do this, we will miss the
chance to do host controller registers (e.g.: CONTROL, POWER, SIGNAL_ENABLE
etc.) settings and also breaks other variables status (e.g. host->pwr). This
is known to break the mmc power off path.
For example:
https://bugs.meego.com/show_bug.cgi?id=19251
Signed-off-by: "Yin, Kangkai" <[email protected]>
--- a/drivers/mmc/host/sdhci.c.old 2011-06-30 10:24:01.776426401 -0700
+++ b/drivers/mmc/host/sdhci.c 2011-06-30 10:24:21.557030243 -0700
@@ -1184,9 +1184,6 @@
pm_runtime_put_autosuspend(host->mmc->parent);
spin_lock_irqsave(&host->lock, flags);
}
- /* no need to configure the rest.. */
- if (host->iosclock == 0)
- goto out;
/*
* Reset the chip on each power off.
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