Hi,
I'm fine tuning power management for TI DM3730 with Android 2.3.4 kernel 2.6.37.
The USB-EHCI hub connects to a Phy (TUSB1210) is plugged with a Sierra 3G module.
We found:
case 1:
When it goes to suspend,the USB-EHCI clock output is off. But we still can't gain enough power saving, For example it still takes A mA
case 2:
Then I remove "usb_ehci_init(&ehci_pdata);" in board-config files, the USB device is complete not loaded when it boots. It takes B mA.
Conclusion:
A-B is around 25mA.
It means even we disable ULPI clock output when it goes to suspend, the USB-EHCI Root Hub still consume 25mA.
Any ideas to reduce this 25mA consumption in suspend mode ??