Date: Wed, 17 Apr 2002 05:40:15 -0700 From: Benjamin Krueger <benjamin@macguire.net> To: Neil Darlow <neil@darlow.co.uk> Cc: freebsd-questions@freebsd.org Subject: Re: DMA limited to UDMA33, non-ATA66 compliant cable error msg Message-ID: <20020417054015.T23267@rain.macguire.net> In-Reply-To: <200204171034.g3HAYVM24163@router.darlow.co.uk>; from neil@darlow.co.uk on Wed, Apr 17, 2002 at 11:34:29AM %2B0100 References: <200204171034.g3HAYVM24163@router.darlow.co.uk>
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* Neil Darlow (neil@darlow.co.uk) [020417 03:34]: > Hi, > > I too observe this message on an ATA-100 capable motherboard with an ATA-66 > compliant cable. > > I ascribe the error to the fact that although the master IDE drive is ATA-66, > my secondary CD-ROM drive (on the same controller) is operating in PIO Mode 4. > > I'm not sure whether the CD-ROM drive is UDMA-capable and is simply set to > use PIO in the BIOS. The next time I have to reboot the system I will check. > > I don't know whether there is a single-device-per-channel limit on ATA-66 > operation. If this were the case, it seems odd that ATA-66 cables are made > with multiple connection points. > > Regards, > Neil Darlow M.Sc. You may not have to reboot at all. If your atapi cdrom supports dma, you can simply set it to use dma while the system is running. The ata(4) driver is configured so that it always attempts to use the highest possible dma mode on all but atapi devices. According to the manpage, they're left in PIO because DMA problems are common with them. You can change this with sysctl on the fly. I won't outline how to do this here because anyone who needs to do so should read the manpage (and subsequent warnings) first. ;) -- Benjamin Krueger "Life is far too important a thing ever to talk seriously about." - Oscar Wilde (1854 - 1900) ---------------------------------------------------------------- Send mail w/ subject 'send public key' or query for (0x251A4B18) Fingerprint = A642 F299 C1C1 C828 F186 A851 CFF0 7711 251A 4B18 To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-questions" in the body of the message
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