Bsrgvty

On my 18.04 machine with stock kernel 4.15, I'm using a run-of-the-mill CSR Bluetooth dongle. Problem now is that the machine will not suspend properly when that dongle is plugged in - it will go to sleep for something between 5 and 10 seconds, but then resume on its own, even if no Bluetooth devices are currently connected or even powered on. When I unplug the dongle before suspend, it stays suspended as it should.

I could just turn off USB wakeup entirely, but I was hoping there's a more nuanced solution that just prevents wakeup via the Bluetooth dongle...

lsusb, usb-devices, hcitool output for dongle:

Bus 001 Device 007: ID 0a12:0001 Cambridge Silicon Radio, Ltd Bluetooth Dongle (HCI mode)

T: Bus=01 Lev=02 Prnt=02 Port=02 Cnt=02 Dev#= 7 Spd=12 MxCh= 0
D: Ver= 2.00 Cls=e0(wlcon) Sub=01 Prot=01 MxPS=64 #Cfgs= 1
P: Vendor=0a12 ProdID=0001 Rev=88.91
S: Product=CSR8510 A10
C: #Ifs= 2 Cfg#= 1 Atr=e0 MxPwr=100mA
I: If#= 0 Alt= 0 #EPs= 3 Cls=e0(wlcon) Sub=01 Prot=01 Driver=btusb
I: If#= 1 Alt= 0 #EPs= 2 Cls=e0(wlcon) Sub=01 Prot=01 Driver=btusb

hci0: Type: Primary Bus: USB
 BD Address: xx:xx:xx:xx:xx:xx ACL MTU: 310:10 SCO MTU: 64:8
 UP RUNNING PSCAN 
 RX bytes:124465 acl:0 sco:0 events:3928 errors:0
 TX bytes:3182 acl:0 sco:0 commands:51 errors:0
 Features: 0xff 0xff 0x8f 0xfe 0xdb 0xff 0x5b 0x87
 Packet type: DM1 DM3 DM5 DH1 DH3 DH5 HV1 HV2 HV3 
 Link policy: RSWITCH HOLD SNIFF PARK 
 Link mode: SLAVE ACCEPT 
 Name: 'monolith'
 Class: 0x0c0104
 Service Classes: Rendering, Capturing
 Device Class: Computer, Desktop workstation
 HCI Version: 4.0 (0x6) Revision: 0x22bb
 LMP Version: 4.0 (0x6) Subversion: 0x22bb
 Manufacturer: Cambridge Silicon Radio (10)

Power off device during suspend, power on during resume

From this answer:

• How to turn off the USB power to my mouse, when I suspend the notebook?

You can create a script called /lib/systemd/system-sleep/cambridge.sh

#!/bin/bash
ZeroBUS1=$(lsusb | grep 0a12:0001 | cut -c 5-7 )
BUS1=$(echo $ZeroBUS1 | sed 's/^0*//') # Strip leading zeros
ZeroBUS2=$(lsusb | grep 0a12:0001 | cut -c 16-18 )
BUS2=$(echo $ZeroBUS2 | sed 's/^0*//') # Strip leading zeros
BUS="$BUS1"-"$BUS2" 

case $1 in
 suspend|suspend_hybrid|hibernate)
 echo "Powering off: $BUS"
 echo "$BUS" | sudo tee /sys/bus/usb/drivers/usb/unbind
 ;;
 resume|thaw)
 echo "Powering on: $BUS"
 echo "$BUS" | sudo tee /sys/bus/usb/drivers/usb/bind
 ;;
esac

Mark the file as executable with

sudo chmod a+x /lib/systemd/system-sleep/cambridge.sh

You may need to reboot for changes to take effect.