Date: Sat, 25 Sep 2004 17:13:11 +0200 From: Ulrich Spoerlein <q@uni.de> To: =?iso-8859-15?Q?S=F8ren?= Schmidt <sos@DeepCore.dk> Cc: current@freebsd.org Subject: Re: regression in ata/atapi wrt dma? Message-ID: <20040925151311.GA9651@galgenberg.net> In-Reply-To: <414DA31E.3090506@DeepCore.dk> References: <200409191627.19011.michaelnottebrock@gmx.net> <414DA31E.3090506@DeepCore.dk>
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[-- Attachment #1 --] On Sun, 19.09.2004 at 17:17:50 +0200, Søren Schmidt wrote: > This is the "new worldorder" for ATAPI devices. The default is now to > enable DMA if the device claims to support at least UDMA33, if not its > left in PIO mode. This is to avoid all the (old) sucky devices that > claims DMA but really doesn't work. > > If you need any modes beyond this, please use atacontrol. I guess something like this is needed then... --- ata.4.orig Wed Sep 22 10:34:19 2004 +++ ata.4 Wed Sep 22 11:11:32 2004 @@ -86,7 +86,7 @@ .It Va hw.ata.ata_dma set to 1 for DMA access, 0 for PIO (default is DMA). .It Va hw.ata.atapi_dma -set to 1 for DMA access, 0 for PIO (default is PIO). +set to 1 for DMA access, 0 for PIO (default is DMA, if the drive supports at least UDMA33). .It Va hw.ata.wc set to 1 to enable Write Caching, 0 to disable (default is enabled). .Em WARNING : @@ -161,8 +161,10 @@ or that one of the devices on the channel only accepts up to UDMA2/ATA33. .Pp -ATAPI devices are set to PIO mode by default because severe DMA problems are -common even if the device capabilities indicate support. +ATAPI devices are set to DMA mode only if they claim to support at least UDMA33. +Older devices claiming DMA or WDMA support get set to PIO by default because +severe DMA problems are common even if the device capabilities indicate +support. You can always try to set DMA mode on an ATAPI device using .Xr atacontrol 8 , but be aware that your hardware might Ulrich Spoerlein -- PGP Key ID: F0DB9F44 Get it while it's hot! PGP Fingerprint: F1CE D062 0CA9 ADE3 349B 2FE8 980A C6B5 F0DB 9F44 "They that can give up essential liberty to obtain a little temporary safety deserve neither liberty nor safety." -- Benjamin Franklin [-- Attachment #2 --] -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.2.6 (FreeBSD) iD8DBQFBVYsHmArGtfDbn0QRAvCWAKDsniUX8ntkU0/q6TyZT2Tfi+MRNgCfaT64 CAATgnvnNRfrJsD1Lw69kB0= =0vfo -----END PGP SIGNATURE-----
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