[Trac #216] Kernel doesn't work w/some USB HDDs

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#216: Kernel doesn't work w/some USB HDDs
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 Reporter:  mfoster  |        Owner:  davidz  
     Type:  defect   |       Status:  reopened
 Priority:  high     |    Milestone:  BTest-1 
Component:  kernel   |   Resolution:          
 Keywords:           |  
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Comment (by blizzard):

 Some notes from Mark:

 {{{
 21:14 < MarkF> USB on this machine involves a complex sequence of
 software.
                Instead of having a nice single USB master, we have
 firmware,
                O.S., drivers, and enumerators all talking to USB.  Each of
                these codebases wants to reset the USB bus.  When the bus
 is
                reset, the core problem that seems to be appearing,
 verified by
                USB protocol analyzer, is that the devices aren't ready
 when he
                code wants them to be.
 21:15 < MarkF> Following the USB reset, even though it seems that devices
 like
                USB Flash keys ought to be ready instantly, they are not.
 They
                sometimes take more than 5 seconds to reset. It's hard to
 see
                this, because the timing obviously depends on the internal
 state
                of their filesystem.
 21:15 < MarkF> The major symptoms of these "drive not ready" problems
 include:
                * OFW missing the USB key and booting NAND Flash instead
 21:16 < MarkF> * The kernel not being able to mount root, and dropping
 into an
                initrd shell saying "No job control for this shell"
 21:16 < MarkF> * Kernel panics (we've seen several types)
 21:17 < MarkF> * Seagate HDDs that sometimes don't work
 21:17 < MarkF> * Hangs at "Starting New Kernel"

 }}}

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Ticket URL: <http://dev.laptop.org/ticket/216#comment:13>
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