Re: [RFC] MMC multiwrite capability removal

From: Alex Dubov
Date: Sun Apr 20 2008 - 10:54:57 EST



--- Pierre Ossman <drzeus-list@xxxxxxxxx> wrote:

> On Sat, 19 Apr 2008 19:34:12 -0700 (PDT)
> Alex Dubov <oakad@xxxxxxxxx> wrote:
>
> >
> > tifm_sd relies on controller to report the number of successfully
> transferred
> > blocks. Of course, I cannot be sure to what extent the controller is
> > trustworthy. It worked fine until now, though.
> >
>
> Sounds like a perfect example of when we have to report 0 upon
> failures. I suspect most controllers will be like this as all the specs
> I've glanced at lack the detail needed to implement a proper sector
> count.
>
> The problems caused by reporting incorrect values here are extremely
> rare and difficult to provoke, so normal testing is not likely to
> uncover it.
>

On the other hand, you may remember that in one of the earlier versions of the
driver I actually counted busy/ready cycles during transfer and from what I
remember, it appeared like controller does the right thing - decrements the
page counter at the "not busy" strobe.



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