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!