Date: Thu, 14 Feb 2002 15:53:46 -0800 From: Kent Stewart <kstewart@owt.com> To: Cliff Sarginson <cliff@raggedclown.net> Cc: vanya <UnixDaemon@vicard.net>, freebsd-questions@FreeBSD.ORG Subject: Re: DMA on ATAPI CD's [ Was Re: About printers ] Message-ID: <3C6C4E0A.2060003@owt.com> References: <000801be3bd9$b17799e0$942a2cc2@og> <20020214214657.GB347@raggedclown.net>
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Cliff Sarginson wrote: > On Sat, Jan 09, 1999 at 05:09:35PM +0300, vanya wrote: > > <snip> (Best to keep unrelated questions in seperate posts). > > >>And one question about DMA for EIDE disks and ATAPI CD. Is DMA automatically >>enabled or user must turn on this option? >> > > I believe DMA is not enabled on ATAPI CD devices, I believe it is > considered a source of possible instability in certain cases (I know > of no proof for this..) .. you can forceably re-enable it by an entry > in sysctl.conf. I have 2 IDE i/faces, with a hard drive and a CD/DVD > on one slave and a CD R/W on another. My line looks as follows: > > hw.atamodes=dma,dma,dma,dma > > You will need to adjust this according to your actual IDE setup, > (i.e. how your ide's are actually configured)... > > "man 8 sysctl.conf" may help. They have add some additional ways of dealing wiht UDMA. For example, my system with a UDMA dvd player shows up with opal:kent> sysctl -a | grep ata kern.ipc.max_datalen: 156 hw.ata.ata_dma: 1 hw.ata.wc: 1 hw.ata.tags: 0 hw.ata.atapi_dma: 1 hw.atamodes: dma,dma,dma,dma, It is the master on the secondary controller. The atapi setting was set in the /boot/loader.conf as loader.conf:hw.ata.atapi_dma="1" It shows up in my dmesg as acd0: DVD-ROM <ATAPI DVD-ROM 16X Maximum> at ata1-master using UDMA66 Kent -- Kent Stewart Richland, WA mailto:kbstew99@hotmail.com http://users.owt.com/kstewart/index.html To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-questions" in the body of the message
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