USB is not resumed(disconnected) after suspend to disk

96boards

#1

Hi all,

I am trying to support suspend to disk(hibernate) on Hikey with 4.4 kernel. During suspend, I could see the usb devices getting reset and I can access them properly. Message can be seen as below:

usb 1-1: reset high-speed USB device number 2 using dwc2
usb 1-1.2: reset high-speed USB device number 3 using dwc2
usb 1-1.2.4: reset high-speed USB device number 4 using dwc2

But after resume, usb gets disconnected and I could not access it anymore:

usb 1-1: USB disconnect, device number 2
usb 1-1.2: USB disconnect, device number 3
usb 1-1.2.4: USB disconnect, device number 4

However “dwc2 f72c0000.usb” gets setup properly. I guess it is OTG. I have connected only keyboard to USB Type-A. OTG is not connected.

Is the dwc2_suspend() and dwc2_resume() functions support only suspend to mem? Is there any hack such that we can forcefully reset the USB(dwc2) on resume in dwc2_resume() code path. I tried adding usb_reset_device() to dwc2_resume() path but that gave a panic as expected. I tried to skip suspend in dwc2_suspend(), but still the usb disconnects.

I added “dwc2_lowlevel_hw_init” to resume path just to check but still no use. Is the power to hub lost or clock is not set properly or something because I could not understand what is the problem.

Below is some more dmesg log:

ivid@ivid:~# dmesg | grep usb
[ 0.408019] usbcore: registered new interface driver usbfs
[ 0.408099] usbcore: registered new interface driver hub
[ 0.408224] usbcore: registered new device driver usb
[ 0.486321] usbcore: registered new interface driver asix
[ 0.486403] usbcore: registered new interface driver ax88179_178a
[ 0.486583] dwc2 f72c0000.usb: Configuration mismatch. Forcing host mode
[ 0.487491] usbcore: registered new interface driver usb-storage
[ 0.581006] usbcore: registered new interface driver usbhid
[ 0.581052] usbhid: USB HID core driver
[ 2.054331] dwc2 f72c0000.usb: Configuration mismatch. Forcing host mode
[ 2.059779] f72c0000.usb supply vusb_d not found, using dummy regulator
[ 2.065133] f72c0000.usb supply vusb_a not found, using dummy regulator
[ 2.939845] dwc2 f72c0000.usb: DWC OTG Controller
[ 2.943587] dwc2 f72c0000.usb: new USB bus registered, assigned bus number 1
[ 2.951537] dwc2 f72c0000.usb: irq 37, io mem 0x00000000
[ 3.342725] usb 1-1: new high-speed USB device number 2 using dwc2

Please let me know if you find anything

Thanks,
Ivid