Does s3cmci driver support DMA data transfer?
tk at maintech.de
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...
Size: 323 bytes
Desc: not available
Url : http://lists.openmoko.org/pipermail/openmoko-kernel/attachments/20080112/4c15f66d/attachment.vcf
More information about the openmoko-kernel