Date: Fri, 08 Feb 2008 19:35:16 +0100 From: Dominic Fandrey <kamikaze@bsdforen.de> To: Tom Evans <tevans.uk@googlemail.com> Cc: "Carlos A. M. dos Santos" <unixmania@gmail.com>, freebsd-stable@freebsd.org Subject: Re: RELENG_7: interrupt eating whole cpu core Message-ID: <47ACA0E4.2030905@bsdforen.de> In-Reply-To: <1202491071.2126.42.camel@localhost> References: <47A9F835.1060200@bsdforen.de> <47AA0696.5020109@bsdforen.de> <7872AB6E-21DA-4E2D-93C0-D07CFA3A7E47@mac.com> <47AA0E3E.4020304@bsdforen.de> <e71790db0802071822l661bdcb8s6dfe5b94be11f0dc@mail.gmail.com> <47ABF66E.4040807@bsdforen.de> <e71790db0802080543g54d27bb8nfdc33e342f982b4@mail.gmail.com> <1202485501.2126.34.camel@localhost> <47AC7FF6.1020801@bsdforen.de> <1202491071.2126.42.camel@localhost>
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Tom Evans wrote: > On Fri, 2008-02-08 at 17:14 +0100, Dominic Fandrey wrote: >> Tom Evans wrote: >>> If I try to turn on DMA, I just get WDMA2, which just doesn't cut it: >> I think any DMA mode is fast enough to handle a DVD drive. There's just no >> necessity for more. >> > > WDMA is not UDMA. Any UDMA variant would be enough. WDMA2 provides a > maximum of 16MiB/s, which will frequently lead to buffer underruns > viewing a DVD. UDMA2 provides a maximum of 33MiB/s, which IS plenty. 16MB/s is exactly what is needed for 12x DVD access. I think this is the usual speed for a Notebook drive nowadays and it suffices for me. >>>> # atacontrol mode acd0 udma5 >>> current mode = WDMA2 >> Same as for me. I'm satisfied with the speed of the drive. > > I'm rarely satisfied - I'm quite often not bothered enough to pursue :) Well, if 12x speed is not enough for you, you have to use an external drive. This is not a driver issue. It's just what your drive supports.
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