Re: [CFT] Bus mastering support for IDE CDROM audio

Kevin P. Fleming
2002-01-28T19:22:03Z

It works very well on my system; I'm now able to rip audio from both drives
in DMA mode (one in UDMA-2, the other in MDMA-2) simultaneously. Even though
they are on the same IDE cable, rip performance increased slightly (average
of 12x per drive, instead of 11x), and CPU usage dropped drastically (less
then 10% usage, even with the WAV files going onto a software RAID-5 array
with ext3 filesystem).

Great job Andrew!

----- Original Message -----
From: "Andrew Morton" <akpm@zip.com.au>
To: "Kevin P. Fleming" <kevin@labsysgrp.com>; "lkml"
<linux-kernel@vger.kernel.org>; "Grant" <gcoady@bendigo.net.au>
Sent: Saturday, January 26, 2002 11:41 PM
Subject: Re: [CFT] Bus mastering support for IDE CDROM audio

> Andrew Morton wrote:
> >
> > "Kevin P. Fleming" wrote:
> > >
> > > When reading from the N drive, get lots of "cdrom_pc_intr: read too
> > > little data 0 < 2352",
> >
> > OK, thanks Kevin (Dan, Kristian, Grant..)
> >
> > Seems that some devices simply terminate their DMA in a normal
> > manner, report no errors and don't tell us how much data they
> > transferred. From my reading of the ATA spec, they're allowed
> > to do that - they only need to report the transfer byte count
> > in PIO mode.
> >
>
> There's an updated patch at
>
> http://www.zip.com.au/~akpm/linux/2.4/2.4.18-pre7/ide-akpm.patch
>
> It now supports multi-frame transfers and should fix the problem
> which you observed.
>
> -
>
>
>