svn commit: r214279 - in head: share/man/man4 sys/cam sys/cam/ata sys/kern

[Alexander Motin]

Bruce Cran wrote:
> On Sunday 24 October 2010 17:31:58 Bruce Cran wrote:
> 
>> Log:
>>   Mostly revert r203420, and add similar functionality into ada(4) since
>> the existing code caused problems with some SCSI controllers.

Proper way would be IMHO to fix polling in aac driver.

>>   A new sysctl kern.cam.ada.spindown_shutdown has been added that controls
>>   whether or not to spin-down disks when shutting down.
>>   Spinning down the disks unloads/parks the heads - this is
>>   much better than removing power when the disk is still
>>   spinning because otherwise an Emergency Unload occurs which may cause
>> damage to the actuator.
> 
> The FLUSH CACHE + STANDBY IMMEDIATE commands are issued (instead of just 
> SLEEP) following the procedure documented in Fujitsu's MHW series product 
> documentation under section 1.10.1, "Recommended power-off sequence".

Not instead of "just SLEEP", but instead of FLUSH CACHE (by respective
peripheral driver) + SLEEP (by xpt). It should probably be the same.

Just for the note, SCSI specification states that STOP automatically
implies FLUSH CACHE. ATA - doesn't.

-- 
Alexander Motin