Add a "spindown" facility to ata-disks: If no requests have been received

for a configurable number of seconds, spin the disk down.  Spin it back
up on the next request.

Notice that the timeout is only armed by a request, so to spin down a
disk you may have to do:

	atacontrol spindown ad10 5
	dd if=/dev/ad10 of=/dev/null count=1

To disable spindown, set timeout to zero:

	atacontrol spindown ad10 0

In order to debug any trouble caused, this code is somewhat noisy on the
console.

Enabling spindown on a disk containing / or /var/log/messages is not
going to do anything sensible.

Spinning a disk up and down all the time will wear it out, use sensibly.

Approved by:	sos

1 files changed, 3 insertions, 0 deletions

diff --git a/sys/dev/ata/ata-all.h b/sys/dev/ata/ata-all.h
index f590c35..28adac9 100644
--- a/sys/dev/ata/ata-all.h
+++ b/sys/dev/ata/ata-all.h
@@ -403,6 +403,9 @@ struct ata_device {
     struct ata_params           param;          /* ata param structure */
     int                         mode;           /* current transfermode */
     u_int32_t                   max_iosize;     /* max IO size */
+    int				spindown;	/* idle spindown timeout */
+    struct callout              spindown_timer;
+    int                         spindown_state;
     int                         flags;
 #define         ATA_D_USE_CHS           0x0001
 #define         ATA_D_MEDIA_CHANGED     0x0002