Date: Tue, 5 Aug 1997 20:27:31 +0200 (MEST) From: Søren Schmidt <sos@sos.freebsd.dk> To: adkin003@gold.tc.umn.edu Cc: current@FreeBSD.ORG Subject: Re: ide_pci, Tyan S1563S, and busmastering dma Message-ID: <199708051827.UAA00589@sos.freebsd.dk> In-Reply-To: <Pine.NEB.3.96.970805085022.436A-100000@samthedog.gold.tc.umn.edu> from dave adkins at "Aug 5, 97 09:47:27 am"
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In reply to dave adkins who wrote: > > Two things prevented the my Tyan S1562D from starting up in busmastering > mode with FastDMA. > > 1) The conditional in generic_dmainit (ide_pci.c) was two restrictive to > allow the Seagate CFA2161A to be recognized as DMA capable. > > 2) The Award bios (v4.01) does not enable FastDMA. > > When generic_dmainit is changed to allow PIO mode 3 drives and piix3 > configuration is added to ide_pci_attach to enable enable FastDMA, the > drive functions fine, and interrupt overhead as seen in sysctl -vm is > about as low as for my NCR pci scsi. > > I also verified that the drive was, infact, using DMA by inserting counter > in wdstart where wdd_dmastart kicks off the DMA. The counter shows usage > for each of the configured drives. I assume that if I get no messages from > the driver, the setup modes for the piix3 and the drives remain > unchanged. > > What are the chances that the code could be changed to have configuration > options to 1) relax the drive mode restrictions, and 2) force FastDMA? For > now I just apply my own patch when I update my sources. Lets have your patches, and we can pretty fast determine if it is safe to use... > The wd driver with FastDMA enabled has been working well for the past > couple of days (since the SMP fix). -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- Søren Schmidt (sos@FreeBSD.org) FreeBSD Core Team Even more code to hack -- will it ever end ..
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