rtcwake suspend to ram & USB boot device

Release: 4.1.36-1

Codename: Arrakis

My boot device is a 8GB USB key. I would like to suspend my system to RAM and I've been testing to accomplish this with rtcwake.

rtcwake -v -m mem -s 60 will suspend my system successfully but errors after wake

Message from watchdog:

The system will be rebooted because of error 19 = 'No such device'

I suspect this is because the USB key does not get re-mounted after suspend.

I believe there's a way to have USB devices persist through suspend with echo 1 >/sys/bus/usb/devices/[USB_ID]/power/persist. [USB_ID] being the device ID, which in my case should be 1e1d:1101

This is my device in question

> usb-devices

T: Bus=02 Lev=01 Prnt=01 Port=03 Cnt=01 Dev#= 2 Spd=480 MxCh= 0

D: Ver= 2.00 Cls=00(>ifc ) Sub=00 Prot=00 MxPS=64 #Cfgs= 1

P: Vendor=1e1d ProdID=1101 Rev=01.00

S: Manufacturer=Kanguru

S: Product=FlashBlu

S: SerialNumber=07023294FA9E3D31

C: #Ifs= 1 Cfg#= 1 Atr=80 MxPwr=200mA

I: If#= 0 Alt= 0 #EPs= 2 Cls=08(stor.) Sub=06 Prot=50 Driver=usb-storage

But there's no such device ID under /sys/bus/usb/devices

user:/sys/bus/usb/devices$ ls

1-0:1.0 2-4 3-0:1.0 4-4 4-5 5-0:1.0 7-0:1.0 usb1 usb3 usb5 usb7

2-0:1.0 2-4:1.0 4-0:1.0 4-4:1.0 4-5:1.0 6-0:1.0 8-0:1.0 usb2 usb4 usb6 usb8

Any feed back would be appreciate.

Hi, mi-hol: I may consider that, thanks. I don't believe that's the issue here though. The option to allow for USB devices to persist has been around since kernel version 3.(?). I just can't figure out why my USB device is not showing under /sys/bus/usb/devices. It should show there as 1e1d:1101 which would then allow me to try out the persist option.

Thank for your feedback.