Date: Sat, 13 May 2006 18:36:48 +0000 From: Marcin Jessa <lists@yazzy.org> To: Dmitry Pryanishnikov <dmitry@atlantis.dp.ua> Cc: des@des.no, harikurniawan@gmail.com, current@freebsd.org Subject: Re: DMA no active on HL-DT-STCD-RW/DVD Message-ID: <20060513183648.7444b11b.lists@yazzy.org> In-Reply-To: <20060513190519.P16055@atlantis.atlantis.dp.ua> 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> <20060513190519.P16055@atlantis.atlantis.dp.ua>
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On Sat, 13 May 2006 19:19:30 +0300 (EEST) Dmitry Pryanishnikov <dmitry@atlantis.dp.ua> wrote: > > 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 Does this mean I should set my laptop's drive mode to WDMA2 instead of UDMA100 (HD) and UDMA33 (CDRW)? Marcin.
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