root@am335x-evm:~# echo mem > /sys/power/state 
[  131.804420] PM: Syncing filesystems ... done.
[  131.845165] Freezing user space processes ... (elapsed 0.001 seconds) done.
[  131.853842] Freezing remaining freezable tasks ... (elapsed 0.001 seconds) done.
[  131.863060] Suspending console(s) (use no_console_suspend to debug)

[  132.286287] PM: suspend of devices complete after 416.373 msecs
[  132.288179] PM: late suspend of devices complete after 1.850 msecs
[  132.291132] PM: noirq suspend of devices complete after 2.914 msecs
[  132.291145] PM: Successfully put all powerdomains to target state
[  132.311708] PM: noirq resume of devices complete after 20.390 msecs
[  132.314105] PM: early resume of devices complete after 2.129 msecs
[  132.316049] net eth0: initializing cpsw version 1.12 (0)
[  132.316074] net eth0: initialized cpsw ale version 1.4
[  132.320318] net eth0: phy found : id is : 0x7c111
[  132.324021] net eth1: initializing cpsw version 1.12 (0)
[  132.328244] net eth1: phy found : id is : 0x7c111
[  137.512514] dpm_run_callback(): usb_dev_resume+0x0/0x18 returns -110
[  137.512585] PM: Device 1-1 failed to resume async: error -110
[  137.513423] PM: resume of devices complete after 5199.288 msecs
[  137.596078] Restarting tasks ... 
[  137.599537] usb 1-1: USB disconnect, device number 2
[  137.613243] done.
root@am335x-evm:~# 
root@am335x-evm:~# [  137.626766] option1 ttyUSB0: GSM modem (1-port) converter now disconnected from ttyUSB0
[  137.658891] option 1-1:1.0: device disconnected
[  137.674922] option1 ttyUSB1: GSM modem (1-port) converter now disconnected from ttyUSB1
[  137.698449] option 1-1:1.1: device disconnected
[  137.713340] option1 ttyUSB2: GSM modem (1-port) converter now disconnected from ttyUSB2
[  137.721519] option 1-1:1.2: device disconnected
[  137.747333] option1 ttyUSB3: GSM modem (1-port) converter now disconnected from ttyUSB3
[  137.770910] option 1-1:1.3: device disconnected
[  137.784430] option1 ttyUSB4: GSM modem (1-port) converter now disconnected from ttyUSB4
[  137.810085] option 1-1:1.4: device disconnected
[  137.822071] qmi_wwan 1-1:1.5 wwan0: unregister 'qmi_wwan' usb-musb-hdrc.0.auto-1, WWAN/QMI device
[  138.142535] usb 1-1: new high-speed USB device number 3 using musb-hdrc
[  138.291537] option 1-1:1.0: GSM modem (1-port) converter detected
[  138.304563] usb 1-1: GSM modem (1-port) converter now attached to ttyUSB0
[  138.314704] option 1-1:1.1: GSM modem (1-port) converter detected
[  138.324369] usb 1-1: GSM modem (1-port) converter now attached to ttyUSB1
[  138.334661] option 1-1:1.2: GSM modem (1-port) converter detected
[  138.344145] usb 1-1: GSM modem (1-port) converter now attached to ttyUSB2
[  138.354221] option 1-1:1.3: GSM modem (1-port) converter detected
[  138.362064] usb 1-1: GSM modem (1-port) converter now attached to ttyUSB3
[  138.373672] option 1-1:1.4: GSM modem (1-port) converter detected
[  138.381424] usb 1-1: GSM modem (1-port) converter now attached to ttyUSB4
[  138.396426] qmi_wwan 1-1:1.5: cdc-wdm0: USB WDM device
[  138.411664] qmi_wwan 1-1:1.5 wwan0: register 'qmi_wwan' at usb-musb-hdrc.0.auto-1, WWAN/QMI device, 9e:6d:ac:65:df:7c