CD-RW/DVD-ROM Combo

[Duane Attaway]

On Tue, 23 Dec 2003, Charles Steinkuehler wrote:

> Is it possible to use DMA with a 2.4 kernel and ide-scsi?  I tried to
> get this going, but it seems stuck in PIO mode, and I typically can't
> burn over 8x w/o making 'coasters'.

I'm using ide-scsi with a 2.4 kernel.  DMA works for me!  You are checking 
the DMA for the IDE interface, not the scsi emulation layer, right?

DMA use is directly a function of your IDE controllers.  This is the
hardware that will assert the DMA interrupts and push information onto the
bus.

If you *really* are determined to get DMA working, there is a way.  If
your controller is connected to the pci bus, check /proc/pci to see what
chip it uses.  The data sheet for that chip will show you what conditions
will allow DMA mode.  It might be the controllers will only use it for
certain types of IDE drives.  The kernel could be forced to tell it to use
it, but if your controllers do not want to, they won't.  The DMA and CPU
share the same memory bus and if it behaves badly, well, the system will
go up in flames.