#6532 BLOC 8.2.0 (: SD Card Corruption

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#6532: SD Card Corruption
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   Reporter:  haralds    |       Owner:  dsaxena             
       Type:  defect     |      Status:  reopened            
   Priority:  blocker    |   Milestone:  8.2.0 (was Update.2)
  Component:  kernel     |     Version:                      
 Resolution:             |    Keywords:  release?            
Next_action:  never set  |    Verified:  0                   
  Blockedby:             |    Blocking:  6893                
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Comment(by gnu):

 When the XO suspends, all USB devices lose power and drop off the USB bus.
 (Other than the WiFi chips, which only drop off the bus.)

 If your USB disk drive was bus-powered, it would spin down.  If it was
 separately powered, it might still go into an odd state when the USB bus
 is powered off.

 On both USB and SD, the installed device may be doing internal processing
 even when the USB bus is idle (e.g. the device's controller chip may be
 erasing flash blocks for later use, or writing buffered data onto
 permanent flash storage).  There's a protocol for when the host wants to
 power down or remove USB or SD devices; I don't think our suspend code
 follows these protocols, so we might power down these devices at a very
 inconvenient time for them, resulting in errors on resume.

 The OLPC's generic USB suspend code also needs the same kind of special-
 case checks that look to see if the same devices are plugged in, and if
 so, resume those devices cleanly without re-mounting.  Currently that code
 only seems to work for the WiFi chip (and maybe now SD).

 Tickets #1423 (closed as if fixed), #2432 (closed as if fixed), #3767
 ("jg: needs TLC after FRS"), #4876 are related.  But there appears to be
 no straightforward, "USB disks die after suspend" bug filed yet; I suggest
 filing one, and copying these entries over, if you can reproduce this.

-- 
Ticket URL: <http://dev.laptop.org/ticket/6532#comment:56>
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