- Add kern.cam.ada.X.write_cache tunables/sysctls to control write caching

on per-device basis.
- While adding support for per-device sysctls, merge from graid branch
support for ADA_TEST_FAILURE kernel option, which opens few more sysctl,
allowing to simulate read and write errors for testing purposes.

1 files changed, 11 insertions, 7 deletions

diff --git a/share/man/man4/ada.4 b/share/man/man4/ada.4
index 66c5c95..c807a4b 100644
--- a/share/man/man4/ada.4
+++ b/share/man/man4/ada.4
@@ -25,7 +25,7 @@
 .\"
 .\" $FreeBSD$
 .\"
-.Dd April 7, 2011
+.Dd April 8, 2011
 .Dt ADA 4
 .Os
 .Sh NAME
@@ -101,7 +101,7 @@ variables and
 .Xr loader 8
 tunables:
 .Bl -tag -width 12
-.It kern.cam.ada.retry_count
+.It Va kern.cam.ada.retry_count
 .Pp
 This variable determines how many times the
 .Nm
@@ -111,23 +111,27 @@ the
 .Nm
 driver dump routine.
 This value currently defaults to 4.
-.It kern.cam.ada.default_timeout
+.It Va kern.cam.ada.default_timeout
 .Pp
 This variable determines how long the
 .Nm
 driver will wait before timing out an outstanding command.
 The units for this value are seconds, and the default is currently 30
 seconds.
-.It kern.cam.ada.spindown_shutdown
+.It Va kern.cam.ada.spindown_shutdown
 .Pp
 This variable determines whether to spin-down disks when shutting down.
 Set to 1 to enable spin-down, 0 to disable.  
 The default is currently enabled.
-.It kern.cam.ada.write_cache
+.It Va kern.cam.ada.write_cache
+.It Va kern.cam.ada. Ns Ar X Ns Va .write_cache
 .Pp
-This variable determines whether device write cache should be enabled or not.
+These variables determines whether device write cache should be enabled
+globally or per-device or disabled.
 Set to 1 to enable write cache, 0 to disable, -1 to leave it as-is.
-The default is currently enabled.
+Values modified in runtime take effect only after device reset.
+The global default is currently enabled.
+The per-device default is to leave it as-is (follow global setting).
 .El
 .Sh FILES
 .Bl -tag -width ".Pa /dev/ada*" -compact