Re: [PATCH] mmc: core: Do not hold re-tuning during CMD6 commands

[Chaotian Jing]

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