Does s3cmci driver support DMA data transfer?

[Thomas Kleffel]

Hi,
>> But it doesn't work and the driver cann't detect the sd card. Does
>> anyone use the s3cmci driver in DMA mode successfully?
>>     
>
> I don't think anyone has used it with DMA in a long time (probably no
> later than 2.6.14 or even 2.6.10).
That's right. And even then DMA did not work reliable. To be honest, it
never did. It always lost and/or corrupted data (about 1 in 10000
transfers or so).

I hunted that problem for quite some time and found what I believed to
be a race condition in the DMA support layer. At the same time, I
noticed that PIO transfers are faster than DMA for small blocks (random
access on FAT). So I decided to drop DMA support and go for a solid PIO
implementation.

Thomas

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