[issue1449] AHCI panic on Intel 6321ESB AHCI

[Matthew Dillon]

    Maybe we can track this down more quickly via IRC instead of 
    email.  on #dragonflybsd.  Once Rumko got online we were able
    to run a ton of test cases in less then an hour.

    If the chipset crash has been fixed maybe cycling the port will
    fix the CI issue this time, so lets try that again.  It also looks
    to me that there is a possible interrupt race.  So try this patch:

	fetch http://apollo.backplane.com/DFlyMisc/ahci12.patch

					-Matt
					Matthew Dillon 
					<dillon at backplane.com>