[issue1449] AHCI panic on Intel 6321ESB AHCI

[Matthew Dillon]

:Alexander Polakov <polachok at gmail.com> added the comment:
:
:>Under what circumstances does the panic occur?  During boot?
:
:Yes, during boot.

    Hmm.  Your AHCI part does not support NCQ so there is no SACT register
    at all on-chip.  Here's a patch which should conditionalize-out the
    SACT register accesses:

	fetch http://apollo.backplane.com/DFlyMisc/ahci07.patch

    The actual crash is an assertion on the CI register, though, so my
    expectation is that it will still crash.

    The ahci port stop/start sequence is supposed to clear CI.  Another
    thing I tried in the patch was to put a delay between the port stop
    and port start, and also after the port start.

    Lets see if either of these adjustments fixes your problem.  if they
    do I'd like you to then remove the ahci_os_sleep() calls I added
    in the patch and test again, so I can determine what actual fix is
    needed.

    If the problem still persists I'm a bit at a loss as the port stop/start
    sequence is always supposed to reset CI to 0.

					-Matt
					Matthew Dillon 
					<dillon at backplane.com>