USB2+umass: timing related bug (machine check abort)

[Marcel Moolenaar]

On Feb 17, 2009, at 8:24 AM, Hans Petter Selasky wrote:

> On Tuesday 17 February 2009, Marcel Moolenaar wrote:
>> Context: MACHINE=ia64, CPU=Montecito
>>
>> I'm running into a timing related MCA. In short:
>> 	...
>> umass0: <HEWLETT PACKARD INTEGRITY SERVER, class 0/0, rev 2.00/0.a1,
>> addr 2> on usbus2
>> umass0:  SCSI over Bulk-Only; quirks = 0x0000
>> umass0:2:0:-1: Attached to scbus2
>> 	*** machine check abort ***
>> ***********************************************************
>> * ROM Version : 01.05
>> * ROM Date    : 11/06/2006
>> * BMC Version :  05.06
>> ***********************************************************
>> 	...
>>
>> When I enable EHCI debugging (level 99) this does not happen
>> and between the debug output, I see:
>>
>
> Hi,
>
> I think that the problem is not USB related, but it happens at a  
> point in time
> where the UMASS USB transfer is half-setup. When the UMASS poll  
> callback is
> called at the wrong time, then you will get a NULL pointer access.  
> Try the
> following patch and report back:
>
> http://perforce.freebsd.org/chv.cgi?CH=157847

No change.

-- 
Marcel Moolenaar
xcllnt at mac.com