[Trac #947] DCONLOAD goes high at S3 entry and exit

[Zarro Boogs per Child]

#947: DCONLOAD goes high at S3 entry and exit
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 Reporter:  wmb at firmworks.com  |       Owner:  mlj      
     Type:  defect             |      Status:  new      
 Priority:  normal             |   Milestone:  Untriaged
Component:  hardware           |    Keywords:           
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 DCONLOAD needs to stay low during suspend so that the DCON can keep the
 screen contents frozen.  But that is not possible with the current wiring.
 It is connected to 5536 GPIO 11, which is also SLP_CLK_EN#.

 When you enter S3 state, the 5536 drives that line high for several
 milliseconds, then releases it.  I measured it drifting down to 0.5 V
 (probably due to R188 which connects to +3.3V, which is not powered during
 suspend).

 When you exit S3 (wakeup), DCONLOAD again goes high, staying there until
 the CPU has had time to reconfigure its GPIO pins.

 During these times when DCONLOAD is high, the DCON loses the display data.

 I'm not sure what the correct solution is.  It might be possible to pull
 DCONLOAD down to GND instead of up to +3.3V, but there is still the
 problem of the 5536 driving it as SLP_CLK_EN# .

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Ticket URL: <http://dev.laptop.org/ticket/947>
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