port-arm/60906: NanoPi NEO emac no longers work with netbsd-10, netbsd-11 and -current

["leot%NetBSD.org@localhost via gnats" <gnats-admin%NetBSD.org@localhost>]

>Number:         60906
>Category:       port-arm
>Synopsis:       NanoPi NEO emac no longers work with netbsd-10, netbsd-11 and -current
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    port-arm-maintainer
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Mon Oct 19 12:00:00 +0000 2026
>Originator:     Leonardo Taccari
>Release:        NetBSD 11.99.9
>Organization:
The missing Ethernet frame
>Environment:
System: NetBSD armv7 11.99.9 NetBSD 11.99.9 (GENERIC) #0: Sun Oct 18 15:24:27 UTC 2026  mkrepro%mkrepro.NetBSD.org@localhost:/usr/src/sys/arch/evbarm/compile/GENERIC evbarm
Architecture: earmv7hf
Machine: evbarm
>Description:
	When trying to use NanoPi NEO emac (ethernet) it seems no longer
	working.
	It worked fine with netbsd-9 so this seems a regression between netbsd-9
	and netbsd-10 (and newer).
	I have tested that with both netbsd-10, netbsd-11 and netbsd-current
	available on armbsd.org as Saturday and today and none of them have
	working ethernet (2026-10-19).

	For completeness here the corresponding dmesg lines (I have "obscured"
	the MAC address both here and in later sections):

	emac0 at simplebus1: EMAC
	emac0: Ethernet address f2:00:3e:xx:xx:xx
	emac0: interrupting on GIC irq 114
	ukphy0 at emac0 phy 1: OUI 0x0088a0, model 0x0000, rev. 0
>How-To-Repeat:
	Run:

	 dhcpcd emac0
	
	Or:

	 ifconfig emac0 192.168.1.28/24 up
	
	And try to ping some host in the network and observe that there are no
	packets and the green LED is always on.

	I can observe that the UTP cable is properly recognized if plugged or
	not though. Here I have kept the default of the image by having dhcpcd
	enabled. When it is plugged I can see (notice "media" and "status"):

	emac0: flags=0x8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> mtu 1500
		capabilities=0x3f00<IP4CSUM_Rx,IP4CSUM_Tx,TCP4CSUM_Rx,TCP4CSUM_Tx>
		capabilities=0x3f00<UDP4CSUM_Rx,UDP4CSUM_Tx>
		enabled=0
		ec_capabilities=0x1<VLAN_MTU>
		ec_enabled=0
		address: f2:00:3e:xx:xx:xx
		media: Ethernet autoselect (100baseTX full-duplex,flowcontrol,rxpause,txpause)
		status: active
		inet6 fe80::37f7:217c:9336:d0e4%emac0/64 flags 0 scopeid 0x1
		inet 169.254.30.240/16 broadcast 169.254.255.255 flags 0
	
	When it is not plugged (notice "media" and "status"):

	emac0: flags=0x8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> mtu 1500
		capabilities=0x3f00<IP4CSUM_Rx,IP4CSUM_Tx,TCP4CSUM_Rx,TCP4CSUM_Tx>
		capabilities=0x3f00<UDP4CSUM_Rx,UDP4CSUM_Tx>
		enabled=0
		ec_capabilities=0x1<VLAN_MTU>
		ec_enabled=0
		address: f2:00:3e:xx:xx:xx
		media: Ethernet autoselect (none)
		status: no carrier
		inet6 fe80::37f7:217c:9336:d0e4%emac0/64 flags 0x8<DETACHED> scopeid 0x1
		inet 169.254.30.240/16 broadcast 169.254.255.255 flags 0x4<DETACHED>

	I have another NanoPi NEO with:

	 NetBSD armv7 9.0_STABLE NetBSD 9.0_STABLE (GENERIC) #0: Tue Jun 30 18:49:17 UTC 2020  mkrepro%mkrepro.NetBSD.org@localhost:/usr/src/sys/arch/evbarm/compile/GENERIC evbarm

	And there emac is properly working. So it is likely a regression between
	netbsd-9 and newer. I have also switched the uSD card to double-check
	that there are no hardware issues in the spare NanoPi NEO I am currently
	testing.
>Fix:
	N/A, sorry!

	If you have any suggestion on how to possibly debug that and/or
	help further I am happy to try!