Reading audio sectors still slow even with DMA enabled
 

Hi all,

I've been wanting to speed up ripping audio CDs with my atapi drive (using ide-scsi). I always got about 60-80% cpu load in kernel mode due to busy waiting for the drive to return the data, and it really bogs down the other processes.
Now couple of weeks ago I upgraded to kernel 2.4.27 which (finally) allowed me to use DMA for cd-rom drives. This didn't work in earlier kernels (I think because audio sectors are not a power of 2 in size). hdparm shows that the drive is indeed in DMA mode. So I expected a big drop in kernel cpu time, but to no avail... Still as slow as before.

I've had better results using a 2.6 kernel (almost no system time used, indicating that DMA is being used), but I won't use that because my video drm driver isn't ported to 2.6 yet so I'm a bit stuck with the 2.4 series :( :(

My question: is the DMA support for atapi cd drives in 2.4.x not (yet) on par with the 2.6 series then? Anyone have an idea if it ever will be?

Thanks in advance!
nukkel