problems with NATA + EHCI + USB harddisk

Matthew Dillon dillon at
Thu Jul 26 13:40:08 PDT 2007

:I got curious about Alexander Shiryaev's USB harddisk bug and just 
:upgraded my system on a USB harddisk to HEAD. It shows some different 
:behavior here:
:All works unless I use _both_ EHCI and NATA. Either one will work fine 
:alone but used together will result in da0 (the USB harddisk) not being 
:detected upon boot, ending on the mountroot> prompt.

    I've seen this too.  If I load EHCI as a module da0 doesn't get detected
    at boot time.

    There's some sort of timing issue.  I'm certain it's not NATA's fault
    but instead it is an issue with assumptions the USB code makes when
    EHCI is present.  EHCI has to take over the OHCI driver and its a real
    mess (and badly designed).

					Matthew Dillon 
					<dillon at>

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