poor performance with W2CBW003 (Marvell 8686)

[hong zhang]

> 4 bit is supported.
> The hardware does not impose unresolvable limitations, the
> 2.6.32 kernel
> gives high performance. But since that kernel is not
> mainstream, it is
> very hard to find out which patch gives the slowdown. git
> bisect
> is not very useful in that situation.
> SD memory card reading speed is always ok (on another of the
> integrated
> sd host controllers).

Have you tested receive throughput? Any difference between TX and Rx throughput?