Date: Tue, 10 Apr 2001 20:27:40 -0400 From: "Brandon S. Allbery KF8NH" <allbery@ece.cmu.edu> To: Cyrille Lefevre <clefevre@poboxes.com> Cc: freebsd-stable@FreeBSD.ORG Subject: Re: ATA_ENABLE_ATAPI_DMA gone? Message-ID: <236930000.986948860@rushlight.rem.cmu.edu> In-Reply-To: <zodo2tsd.fsf@gits.dyndns.org>
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On Wednesday, April 11, 2001 01:56:34 +0200, clefevre-lists@noos.fr wrote: +---- | "Bruce A. Mah" <bmah@FreeBSD.ORG> writes: | | > > It seems that they've been moved, the new ata(4) explains how to set | them > > (ie from the loader) | > | > And it's also mentioned in RELNOTES.TXT: | > | > # To provide more flexible configuration, the various options for the | > # ata(4) driver are now boot loader tunables, rather than kernel | > # configure-time options. | | the ata(4) manual page isn't clear about the difference between | hw.ata.ata_dma (where ata-disk.c says ATA disk DMA mode control) and | hw.ata.atapi_dma (where atapi-all.c says ATAPI device DMA mode control) ? +--->8 As I understand it, ATA disks generally support DMA, and ATAPI devices (floppies, tapes, CDROM/CDRW, etc.) generally don't; but some (many?) ATAPI devices claim to support it due to buggy firmware. So you have to enable DMA for ATAPI devices manually, if you want it and you know that you have ATAPI devices which don't falsely report DMA capability. -- brandon s. allbery [os/2][linux][solaris][japh] allbery@kf8nh.apk.net system administrator [WAY too many hats] allbery@ece.cmu.edu electrical and computer engineering KF8NH carnegie mellon university ["better check the oblivious first" -ke6sls] To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-stable" in the body of the message
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