[MX25][MMC] mmc esdhc failure in 3.3

[Eric Bénard]

Hi Joan Carles,

Le Tue, 27 Mar 2012 10:46:45 +0200,
joancarles <joancarles at fqingenieria.es> a écrit :
> >> This is still present, and we have absolutely no idea where to 
> >> continue
> >> searching for the solution of the problem. Any pointers? Any git 
> >> trees
> >> of mmc driver changes we could try? Anybody else with a MX25 that 
> >> has
> >> this issue?
> >>
> > does that attached patch fix your problem ?
> 
> YES, indeed it does to a certain degree. The timeout errors do not 
> occur anymore and I can successfully perform many fs->ops, such as READ, 
> WRITE, UNLINK ... . So thank you very much for this insight through your 
> patch!
> 
> The speed of the card is excruciatingly slow, however. We roughly get 
> between 34KB/s and 64KB/s from a dd if=/dev/zero write to any of the 
> following partitions:
> 
I have the same speed problem here on i.MX25 but still haven't found
the reason.
Shawn, Richard : do you have an idea of why the eSDHC is so slow on
i.MX25 ?

Thanks,
Eric