From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <727a9da5ec3ea5e97ff9915bd10ca365@plan9.bell-labs.com> Date: Thu, 21 Sep 2006 20:29:42 -0400 From: jmk@plan9.bell-labs.com To: 9fans@cse.psu.edu Subject: Re: [9fans] Re: venti+fossil problems on new install In-Reply-To: MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit Topicbox-Message-UUID: be606948-ead1-11e9-9d60-3106f5b1d025 No. Whether DMA works is a function of 1) we recognise the chip as one we can programme for DMA; 2) the modes for DMA are set consistently in both the chip AND in the drive. The Plan 9 ATA code does not check or programme the modes in chips or devices, it assumes the BIOS has done so. While we could go some way towards that (e.g. programming the drive is usually just sending it a command and the way to set the modes appropriately in some chips is documented (e.g. most of the Intel ones we handle, though it differs there from chip to chip too), in my opinion the juice ain't worth the squeeze. On Thu Sep 21 20:06:36 EDT 2006, quanstro@quanstro.net wrote: > oh. okay. since most ATA controllers are listed chipset-by-chipset, couldn't the > known working ones have dma enabled by default? > > - erik