cvs commit: src/sys/dev/mpt mpt.c mpt.h mpt_cam.c

[mjacob at freebsd.org]

Awesome! Thanks1

On Sun, 3 Jun 2007, Scott Long wrote:

> scottl      2007-06-03 23:13:05 UTC
>
>  FreeBSD src repository
>
>  Modified files:
>    sys/dev/mpt          mpt.c mpt.h mpt_cam.c
>  Log:
>  mpt.c:
>  mpt.h:
>          Add support for reading extended configuration pages.
>  mpt_cam.c:
>          Do a top level topology scan on the SAS controller.  If any SATA
>          device are discovered in this scan, send a passthrough FIS to set
>          the write cache.  This is controllable through the following
>          tunable at boot:
>
>          hw.mpt.enable_sata_wc:
>                  -1 = Do not configure, use the controller default
>                   0 = Disable the write cache
>                   1 = Enable the write cache
>
>          The default is -1.  This tunable is just a hack and may be
>          deprecated in the future.
>
>  Turning on the write cache alleviates the write performance problems with
>  SATA that many people have observed.  It is not recommend for those who
>  value data reliability!  I cannot stress this strongly enough.  However,
>  it is useful in certain circumstances, and it brings the performence in line
>  with what a generic SATA controller running under the FreeBSD ATA driver
>  provides (and the ATA driver has had the WC enabled by default for years).
>
>  Revision  Changes    Path
>  1.42      +154 -29   src/sys/dev/mpt/mpt.c
>  1.41      +55 -3     src/sys/dev/mpt/mpt.h
>  1.57      +305 -0    src/sys/dev/mpt/mpt_cam.c
>