Any objections/comments on axing out old ATA stack?

[Matthias Andree]

I have just sent more information to the PR at
http://www.freebsd.org/cgi/query-pr.cgi?pr=157397

The short summary (more info in the PR) is:

- limiting tags to 31 does not help

- disabling NCQ appears to help in initial testing, but warrants more
testing

- error happens during WRITE_FPDMA_QUEUED,

- File system in question is SU+J UFS2 mounted on /usr, and I can for
instance "rm -rf /usr/obj" or just log into GNOME and try to open a
gnome-terminal to trigger stalls;

- Linux uses 31 tags (for different reason) and has no drive quirks, but
a controller quirk;

for Jeremy's topic #6, regarding the ATI/AMD SB7x0 that I am using, it
might be worthwhile investigating the AHCI_HFLAG_IGN_SERR_INTERNAL flag
- it gets set by Linux on the SB700 that my computer is using, see
ahci_error_intr() in libahci.h - I am not going to interpret that for
lack of expertise, but it does affect error handling and appears to
ignore a certain condition.

Why only my Samsung HDD drive triggers this but not the WD drive, I do
not know yet.

Hope that helps a bit.


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