r8152 4-1.4:1.0 enx18dbf22dccf3: failed tx_urb -13

Dear Linux folks,


On the Dell XPS 9360, testing Linux 5.8-rc4 from the Ubuntu Linux Kernel 
Mainline PPA [1], when running

     sudo ./sleepgraph.py -config config/suspend.cfg -multi 50 15

Linux logged the messages below *once* during suspend with the Dell 
DA200 USB-C port replicator(?) attached, and a network cable plugged in 
there.

     [ 1041.538065] r8152 4-1.4:1.0 enx18dbf22dccf3: failed tx_urb -13

Does somebody know more about the warning [2]? What does error code -13 
mean returned by `r8152_tx_agg_fill(()`?


Kind regards,

Paul


[1]: https://kernel.ubuntu.com/~kernel-ppa/mainline/v5.8-rc4/
[2]: 
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/drivers/net/usb/r8152.c#n2402