xref: /aosp_15_r20/external/sg3_utils/README.sg_start (revision 44704f698541f6367e81f991ef8bb54ccbf3fc18)
1Hi,
2
3you can use sg_start to start (spin-up, 1) and stop (spin-down, 0) devices.
4I also offers a parameter (-s) to send a synchronize cache command to a
5device, so it should write back its internal buffers to the medium.
6
7Be aware that the Linux SCSI subsystem at this time does not automatically
8starts stopped devices, so stopping a device which is in use may have fatal
9results for you.
10
11So, you should apply with care.
12I use it in my shutdown script at the end (before the poweroff command):
13
14# SG_SHUG_NOS is set in my config file rc.config
15# SG_SHUT_NOS="0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15"
16if test -x /bin/sg_start; then
17    if test "`basename $command`" = "reboot"; then
18        for no in $SG_SHUT_NOS;
19	      do /bin/sg_start /dev/sg$no -s >/dev/null 2>&1;
20	 done
21    else
22        for no in $SG_SHUT_NOS;
23	    do /bin/sg_start /dev/sg$no -s 0 >/dev/null 2>&1;
24        done
25    fi
26fi
27
28Enjoy!
29Kurt Garloff
30
31
32Postscript
33==========
34sg_start has been reworked to allow a block device (e.g. /dev/sda) in
35addition to the sg device name (e.g. /dev/sg0) in the lk 2.6 series.
36sg_start now has more command line options, see its man page.
37
38	Douglas Gilbert <dgilbert at interlog dot com> 2004/5/8
39