I am trying to make the power consumption further low in system suspend(to mem) case in Jetson TX2.
Linux Kernel is from L4T 27.1.
For that I removed keep-power-in-suspend for sdhci4 node from device-tree.
But resume says,
mmc0: error -110 during resume (card was removed?)
and system resume fails as eMMC is not accessible.
I think the current MMC driver is not re-enabling the card power.
In my understanding, that property is used for keeping the card power ON even while controller is OFF.
I am trying for power off and power on back of eMMC and resume properly so while suspended, the power will be minimized a little bit.
Also I did no find the schematics for the eMMC interface.
I think the eMMC sits on the Jetson module and not in the motherboard.
I think, the schematics I could download from nvidia download centre is only for motherboard.
Can anyone have comments/helps on this?
it’s expected that you got failure after removing keep-power-in-suspend, please refer to the mmc documentation at below path.
keep-power-in-suspend: Preserves card power during a suspend/resume cycle
Thanks for quick reply.
I understand that keep-power-in-suspend DT property is used for preserving card power.
But I was expecting the current driver would disable card power during suspend and re-enable during resume if that DT property is removed.
But it seems current driver cannot work without keep-power-in-suspend.
I tried the same for some other vendor boards (eg: Freescale SabreSD) and those drivers can work with/without keep-power-in-suspend property.
Can you share the failing logs?
could you please test this again with JetPack-3.2 Developer Preview ?