Messages in this thread |  | | | Date | Sat, 28 Nov 1998 01:23:09 -0600 (CST) | | From | "Andre M. Hedrick" <> | | Subject | Re: UDMA is NFG on Ultra33 (CMD646 in disguise) |
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On Wed, 25 Nov 1998, David S. Miller wrote:
> > Mark when will you listen? Let me try this once more. > > CMD646U chipsets, without hardware hacks, cannot be safely used in > _any_ UDMA mode whatsoever. > > Several months ago, while you were still the IDE maintainer, I sent > you a precise description of this hardware bug in an email when I > found it during my coding of the driver for sparc64/PCI. And I also > told you the exact hardware change which is necessary to fix this, and > therefore why UDMA could not be enabled in a 646U driver we want any > users to use.
Would you care to forward that for my records and postarity (sp).
> Don't fight this, if UDMA0 works for you, it is by luck and you are > hitting the edge of the chips reliable configuration. I know, becuase > I stuck a logic analyzer on these chips until the CMD people would > cough up an errata sheet for me. > > So I ask that you please don't encourage the current IDE maintainers
I have not taken to job yet......I am filling in until........ > to even think about adding support for any UDMA mode on cmd646U > chipsets.
Done.....if it does not come natural I usually don't force the issue. It is clear to me from you that cmd646U is DMA mode 2 limited.... Since I don't have this card/chipset and you say it is buggy.....I am not going to bother........and will discourage others from doing so, too. > Later, > David S. Miller > davem@dm.cobaltmicro.com >
Cheers, Andre Hedrick The IDE-FNG for Linux The APC UPS Specialist for Linux
http://www.dyer.vanderbilt.edu/server/udma/ http://www.dyer.vanderbilt.edu/server/apcupsd/apcupsd-3.5.0.bin.tar.gz
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