Date: Sat, 13 May 2006 19:19:30 +0300 (EEST) From: Dmitry Pryanishnikov <dmitry@atlantis.dp.ua> To: "Angka H. K." <harikurniawan@gmail.com> Cc: =?ISO-8859-1?Q?Dag-Erling_Sm=F8rgrav?= <des@des.no>, current@freebsd.org Subject: Re: DMA no active on HL-DT-STCD-RW/DVD Message-ID: <20060513190519.P16055@atlantis.atlantis.dp.ua> In-Reply-To: <4c40c4e70605130835v46296d6akcc0bdd44bec49d08@mail.gmail.com> References: <4c40c4e70605130152s52fb3188nd847a0b8b0d46972@mail.gmail.com> <861wuy8b84.fsf@xps.des.no> <4c40c4e70605130418y3208840ctb0b1c7b1f61b7a74@mail.gmail.com> <86wtcq6psi.fsf@xps.des.no> <4c40c4e70605130659q4c486a64u188177bd5eb804f5@mail.gmail.com> <86hd3u6lbc.fsf@xps.des.no> <4c40c4e70605130744o5d0fd566n6a219ade5924561d@mail.gmail.com> <86d5ei6k3x.fsf@xps.des.no> <4c40c4e70605130835v46296d6akcc0bdd44bec49d08@mail.gmail.com>
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Hello! On Sat, 13 May 2006, Angka H. K. wrote: > By the way what is WDMA and why it saying PIO not WDMA ? WDMA corresponds to so-called "multiword DMA" transfer mode. It's slower than UDMA (IIRC WDMA2 gives 16Mbytes/s, same as PIO4), but still should be sufficient for CD/DVD drive (well, up to 8x-speed DVDs). Of course, it's better to use WDMA2 than PIO4 because WDMA (as well as UDMA) doesn't use CPU cycles for moving data between RAM and device. FreeBSD's ata driver is quite conservative, and doesn't automatically enable WDMA mode for ATAPI device even if hw.ata.atapi_dma=1, so you should just enable this mode with atacontrol. E.g., you can add /sbin/atacontrol mode acd0 wmda2 to your /etc/rc.local file. Sincerely, Dmitry -- Atlantis ISP, System Administrator e-mail: dmitry@atlantis.dp.ua nic-hdl: LYNX-RIPE
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