[Trac #340] Marvell Wireless Upgrades: Hubs on other USB ports cause failures!

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#340: Marvell Wireless Upgrades: Hubs on other USB ports cause failures!
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 Reporter:  mfoster  |        Owner:  mbletsas
     Type:  defect   |       Status:  new     
 Priority:  blocker  |    Milestone:  BTest-1 
Component:  distro   |   Resolution:          
 Keywords:           |  
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Comment (by mfoster):

 Hi, Gang,

 New information.  First, we asked some USB experts from Quanta to take a
 look at this problem. They brought along a high end LeCroy USB protocol
 analyzer.  We used a slightly different technique to induce wireless
 failure.  In this case, we booted with only the wireless and an empty USB2
 hub, then plugged in a keyboard.  The insertion of the keyboard into the
 hub consistenyl triggered wireless failures.  We could see this in two
 ways.  First, if we attempted to program the Boot2 ROM, the programming
 would fail.  Second, if we instead attempted to load the wireless driver,
 the driver would get into an infinite loop where it would attempt to load
 the firmware, fail, reset the wireless module, and repeat that cycle
 forever.

 The Quanta engineers analyzed this failure, and found the following
 comparison between good and failed transactions:

 http://www.talix.com/Marvell_Failure.gif

 Their summary is that it looks as though the chip may have gotten confused
 about the size of its FIFO and accepted a too-long data burst.  In the
 good transaction, we see  that the 88W8388 immediately returns a NYET
 condition.  In the bad transaction, it sends an ACK after 5.3 seconds!

 We'll leave further analysis of these failures to Marvell, because the
 next comment contains our workaround solution.

-- 
Ticket URL: <http://dev.laptop.org/ticket/340#comment:1>
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