On Sun, Oct 24, 2010 at 10:55 AM, Alexander Motin <m...@freebsd.org> wrote: > Garrett Cooper wrote: >> On Sun, Oct 24, 2010 at 10:03 AM, Alexander Motin <m...@freebsd.org> wrote: >>> 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. >> >> I could be wrong, but I think the ANSI ATA<->SCSI spec states >> otherwise (taken from ANSI INCITS 431-2007 page 62 -- see steps 1-4): >> >> 9.11.3 START STOP UNIT START bit LOEJ bit combinations >> The SATL shall perform the actions shown in table 40 in response to a >> START STOP UNIT command. >> Table 40 — Definition of START and LOEJ bits in the START STOP UNIT CDB >> START LOEJ Definition >> 0 0 The SATL shall: >> 1) If the IMMED bit is set to one, then return GOOD status; >> 2) Issue an ATA flush command (see 3.1.11) to the ATA device; >> 3) If the ATA flush command completes with any error, then process ending >> status >> according to the IMMED bit (see 9.11.2) with the additional sense code set to >> COMMAND SEQUENCE ERROR; >> 4) If the ATA flush command completes without error, then issue an ATA >> STANDBY >> IMMEDIATE command to the ATA Sector Count set to zero; >> 5) If the ATA STANDBY IMMEDIATE command completes with any error, then >> process ending status according to the IMMED bit (see 9.11.2) with the >> additional >> sense code set to COMMAND SEQUENCE ERROR; and >> 6) If the ATA STANDBY IMMEDIATE command completes without error and the >> IMMED bit is set to zero, then return GOOD status (see 9.11.2) a. >> >> Not sure about the ATA spec standalone... might be present in the ATA8 >> spec. > > As I understand, this just confirms what I have said: > SCSI STOP == ATA FLUSH CACHE + STANDBY IMMEDIATE. > So SCSI STOP implies flush, while ATA STANDBY IMMEDIATE doesn't.
Looking at it from that perspective, I agree. _______________________________________________ svn-src-head@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/svn-src-head To unsubscribe, send any mail to "svn-src-head-unsubscr...@freebsd.org"
