In testing networking with EFI/u-boot, there is an issue where the dwc2 USB controller will hang -- requiring an USB reset. The issue appears to be the programming of the "Bulk-In Empty Response" in the lan78xx controller. The patch is a suggested fix.
However, I am not familiar enough with neither the lan78xx nor the dwc2 to know whether this is the best, or even most appropriate, fix.
The issue arises readily with EFI/u-boot programs, such as grub: the uboot EFI code will periodically poll the network adapter to see if it has received a packet. Generally speaking no packet has arrived and the attempt to receive will immediatly hang the dwc2 controller. The console will show this message:
Rx: failed to receive: -5
Interestingly, the issue will not arise with request/response protocols, such as u-boot's dhcp command.
Andrew Thomas (1): dwc2 USB controller hangs with lan78xx
drivers/usb/eth/lan78xx.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)