[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):

 After a comment by Alan about the wireless module's reset this morning, we
 began to see if manually resetting the wireless module would help to get
 the chip out of the error conditions we've been seeing.  Simply connecting
 the pin to ground in fact worked perfectly.  Every time we would induce
 the failure conditions, resetting the module would get everything back to
 proper functionality.

 Skip forward about 6 hours, and we have a simple hardware fix that we will
 ECO into the B1 systems.  If you look at the EC chip on the B1 boards
 (this is also on the pre-B boards), there is a test point T188 connected
 to the EC's GPIOEE pin.  Connecting a wire from that point to the wireless
 module's Reset pin allows us the provision to control the wireless reset
 in software.  We then asked Ray to change the EC code to ensure that the
 GPIOEE pin is left in a tri-state/input condition, allowing the wireless
 module to be reset normally.  As a third component, David Woodhouse
 changed the Libertas driver to incorporate activation of the wireless
 reset line whenever the existing code attempts to reset the module. At the
 moment, this is a very long 500 mS (>10X longer than necessary) to ensure
 that when it happens, it'll be visible. While the wireless module is held
 in reset, the wireless activity light will remain off.

 With these changes, the wireless module works perfectly in our testing
 thus far.  We still will need real fixes from Marvell, but this change
 appears to have dramatically improved the stability of wireless in the
 OLPC system.

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Ticket URL: <http://dev.laptop.org/ticket/340#comment:2>
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