Mark Lord wrote:
Alan Cox wrote:
On Fri, 13 Apr 2007 13:08:31 -0400
Kyle McMartin <kyle@xxxxxxxxxxxxx> wrote:
READ_NATIVE_MAX and SET_MAX were causing timeouts on sata_nv
controllers.
Disabling ADMA helped, but that is quite a large hammer to use.
Reverting
382a6652e91b34d5480cfc0ed840c196650493d4 also helped, but we might as
well
fix it right, instead of disabling the performance gain on cache flushes
by using ADMA mode.
Probably not going to make any performance difference to blacklist all
non-data commands or all but a few like cache-flush.
I agree. The Pacific Digital ADMA stuff had some quirks for various
non-data
commands as well, and the sensible thing was to just not use ADMA for
anything
other than READs/WRITEs and possible CACHE FLUSHes.
I'm told by NVidia that non-data commands should be fine in ADMA mode,
except for those that require reading back a result taskfile (which
can't be done in ADMA mode). The patch in libata-dev which I mentioned
in another email will ensure that we don't try to use ADMA for such
commands, so this patch should not be needed.
--
Robert Hancock Saskatoon, SK, Canada
To email, remove "nospam" from hancockr@xxxxxxxxxxxxx
Home Page: http://www.roberthancock.com/
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