[Trac #215] ECC data for empty block is not all 0xFF

[Zarro Boogs per Child]

#215: ECC data for empty block is not all 0xFF
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 Reporter:  dwmw2   |       Owner:  blizzard
     Type:  defect  |      Status:  new     
 Priority:  normal  |   Milestone:  BTest-1 
Component:  distro  |    Keywords:          
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 Typically, we should arrange for the ECC data matching a fully erased
 block to be all 0xFF. That way, there isn't an ECC error when you read an
 empty block. Without that being done properly, we have to put a special
 case in to the error correction code, to check for a fully-empty block
 which triggers a false error.

 Currently, the ECC for 2KiB of 0xFF is as follows:
 41 a0 71 65 54 27 f3 93 ec a9 be ed 0b a1

 A simple way to fix this would be to XOR the ECC data with { be 5f 8e 9a
 ab d8 0c 6c 13 56 41 12 f4 5e } when we write it to (and read it from) the
 medium. A different pattern would be needed in 512-byte mode.

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Ticket URL: <http://dev.laptop.org/ticket/215>
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