Does s3cmci driver support DMA data transfer?

Thomas Kleffel tk at
Sat Jan 12 00:21:39 CET 2008

>> 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


-------------- next part --------------
A non-text attachment was scrubbed...
Name: tk.vcf
Type: text/x-vcard
Size: 323 bytes
Desc: not available
Url : 

More information about the openmoko-kernel mailing list