Spin down HDD after disk sync or before power off

[Andrew Duane]

________________________________________
From: owner-freebsd-hackers at freebsd.org [owner-freebsd-hackers at freebsd.org] On Behalf Of Warren Block [wblock at wonkity.com]
Sent: Wednesday, February 03, 2010 7:43 PM
To: Erich Dollansky
Cc: freebsd-hackers at freebsd.org
Subject: Re: Spin down HDD after disk sync or before power off

On Thu, 4 Feb 2010, Erich Dollansky wrote:
> In case of a reboot, it is already known when the command is given that the machine will restart without being powered of.
>
> If you spin-down the disk, you lose one start cycle.
>
> It is not that important but if it can be done with just one if, please, just do it.

AFAICT ad_shutdown can't tell whether it's called for a reboot or a
poweroff, it's just told to "shut down".  So maybe it's one if, but it's
somewhere above ata-disk.c but below reboot(RB_POWEROFF).

-Warren Block * Rapid City, South Dakota USA
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You can register for a shutdown even that *does* get to know the "howto" variable; we do this quite a bit on some of our platforms that need special handling at power-off versus halt.

    extern void jsrxnle_poweroff_devices(void *junk, int howto);

    /* Registering power-off handler to be called at the system shutdown */
    EVENTHANDLER_REGISTER(shutdown_final, jsrxnle_poweroff_devices, NULL, SHUTDOWN_PRI_LAST + 10);

The howto argument can be checked for RB_POWEROFF:

    if (howto & RB_POWEROFF) {
           /* Spin Down */
    }

--
Andrew Duane             Juniper Networks
978-589-0551              10 Technology Park Dr
aduane at juniper.net      Westford, MA  01886-3418