Ticket #947 (closed defect: fixed)
DCONLOAD goes high at S3 entry and exit
|Reported by:||wmb@…||Owned by:||wad|
|Keywords:||Cc:||wmb@…, jordan.crouse@…, arnold.Kao@…, mlj, smithbone@…|
|Deployments affected:||Blocked By:|
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# .