Linux/AM4377: USB does not resume from suspend

Hi Beate,

The procedure you did has two problems.

1. Please don't modify the power entries for 'xxxxxxxx.omap_dwc3/xxxxxxxx.usb', that is for the usb controllers, not the usb bus.

2. Using a usb thumb drive to do this test is not a good idea, Linux has a complex driver stack to use mass storage, so it is not that clear how to control the bus suspend/resume with a thumb drive. Better to use a usb mouse or keyboard (with no built-in hub).

How to run the test:

1. Check the mouse enumeration log to find the usb device node. For example,

[  723.302429] usb 1-1: new low-speed USB device number 4 using xhci-hcd
[  723.501709] input: Logitech Optical USB Mouse as /devices/platform/44000000.ocp/483c0000.omap_dwc3/483d0000.usb/xhci-hcd.3.auto/usb1/1-1/1-1:1.0/0003:046D:C016.0002/input/input3
[  723.520938] hid-generic 0003:046D:C016.0002: input: USB HID v1.10 Mouse [Logitech Optical USB Mouse] on usb-xhci-hcd.3.auto-1/input0

the log shows the mouse is enumerated as '1-1'.

2. go to the sysfs entry of usb device '1-1':

cd /sys/bus/usb/devices/1-1/power

3. now control and check the usb bus suspend/resume:

root@am437x-evm:power# cat autosuspend
2
root@am437x-evm:power# cat control 
on
root@am437x-evm:power# cat runtime_status 
active
root@am437x-evm:power# echo auto > control 
root@am437x-evm:power# cat runtime_status 
suspended
root@am437x-evm:power# echo on > control 
root@am437x-evm:power# cat runtime_status 
active

Hi Beate,

I haven’t heard back from you, I’m assuming you were able to resolve your issue. If not, just post a reply below (or create a new thread if the thread has locked due to time-out). thanks.