[Trac #280] Video output is delayed after DCON -> GPU transition

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#280: Video output is delayed after DCON -> GPU transition
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 Reporter:  JordanCrouse  |       Owner:  JordanCrouse
     Type:  defect        |      Status:  new         
 Priority:  blocker       |   Milestone:  BTest-1     
Component:  kernel        |    Keywords:              
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 Questions from dwmw2 that need answering by AMD:

 1. What causes that delay after powerup -- what's happening between 38ms
 and 92ms in the trace? Just the video output circuits being slow to power
 up? (http://david.woodhou.se/dconvga-2.png).

 2. Precisely what timing should we expect for this? What is the minimum
 and what the maximum time it could take. As I said, I've seen something
 like 20ms-50ms in my own testing.

 3. Is there a way we could poll for completion, or do we just have to wait
 for however long you say is the maximum when you answer question 2?

 JordanCrouse adds another question:

 4. What is the optimal sequence for turning back on the graphics engine in
 the shortest amount of time possible?

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Ticket URL: <http://dev.laptop.org/ticket/280>
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