[MPlayer-users] Re: mplayer and preemptible kernel

[Tobias Diedrich]

Nyk Tarr wrote:

> >From what I read on the linux kernel mailing list, ide-scsi does not
> support dma. I suspect it never will as the only things that use it
> (programs that need direct access to cd-rom/cd-rw etc. hardware) will
> have a new interface to use in the next stable release. Oh, and the new
> IDE code (>2.5.somethingorother) can have both ide-cd and ide-scsi
> loaded for the same device.

Ok, I just did some short tests:

I have an IDE-DVDROM on /dev/hdd, I use ide-scsi and access this as
/dev/scd0. I use kernel 2.4.19-ac4. By default DMA is enabled on all my
IDE channels.
If I put in a _data_ cdrom and do dd if=/dev/scd0 of=foo top shows ~9%
system load. 
After doing hdparm -d0 /dev/hdd this jumps to ~80% system load.

So I'd say it's very clear that DMA _does_ work with ide-scsi.

_However_ I know that it _does not_ work when _ripping audio_.
But that is not different wether you use ide-scsi or not to access your
CDROM.

-- 
Tobias								PGP: 0x9AC7E0BC
This mail is made of 100% recycled bits
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