Re-enable CTL in GENERIC on i386 and amd64, but turn on the CTL disable

tunable by default.

This will allow GENERIC configurations to boot on small memory boxes, but
not require end users who want to use CTL to recompile their kernel.  They
can simply set kern.cam.ctl.disable=0 in loader.conf.

The eventual solution to the memory usage problem is to change the way
CTL allocates memory to be more configurable, but this should fix things
for small memory situations in the mean time.

UPDATING:		Explain the change in the CTL configuration, and
			how users can enable CTL if they would like to use
			it.

sys/conf/options:	Add a new option, CTL_DISABLE, that prevents CTL
			from initializing.

ctl.c:			If CTL_DISABLE is turned on, don't initialize.

i386/conf/GENERIC,
amd64/conf/GENERIC:	Re-enable device ctl, and add the CTL_DISABLE
			option.

1 files changed, 4 insertions, 1 deletions

diff --git a/sys/amd64/conf/GENERIC b/sys/amd64/conf/GENERIC
index 3988195..577cf4b 100644
--- a/sys/amd64/conf/GENERIC
+++ b/sys/amd64/conf/GENERIC
@@ -138,7 +138,10 @@ device		sa		# Sequential Access (tape etc)
 device		cd		# CD
 device		pass		# Passthrough device (direct ATA/SCSI access)
 device		ses		# Enclosure Services (SES and SAF-TE)
-#device		ctl		# CAM Target Layer
+device		ctl		# CAM Target Layer
+options		CTL_DISABLE	# Disable CTL by default to save memory.
+				# Re-enable with kern.cam.ctl.disable=0 in
+				# /boot/loader.conf
 
 # RAID controllers interfaced to the SCSI subsystem
 device		amr		# AMI MegaRAID