Hello again,

On Thu, 29 May 2025 17:36:11 +0800
Jijie Shao [off-list ref] wrote:

Hi Maxime,  fc81e257d19f ("net: phy: phy_caps: Allow looking-up link caps based on speed and duplex") might have different behavior than the modification.
My case is set 10M Half with disable autoneg both sides and I expect it is
link in 10M Half. But now, it is link in 10M Full，which is not what I
expect.

I used followed command and trace how phy worked.
	ethtool -s eth1 autoneg off speed 10 duplex half
The log is showed as followed:
ethtool-13127	[067]	6164.771853: phy_ethtool_ksettings set: (phy_ethtool ksettings set+0x0/0x200) duplex=0 speed=10
kworker/u322:2-11096	[070]	6164.771853:	_phy_start_aneq: ( _phy_start_aneg+0x0/0xb8) duplex=0 speed=10
kworker/u322:2-11096	[070]	6164.771854:	phy_caps_lookup: (phy_caps_lookup+0x0/0xf0) duplex=0 speed=10
kworker/u322:2-11096	[070]	6164.771855:	phy_config_aneg: (phy_config_aneg+0x0/0x70) duplex=1 speed=10
kworker/u322:2-11096	[070]	6164.771856:	genphy_config_aneg:	(__genphy_config_aneg+0X0/0X270) duplex=1 speed=10

I managed to get a bit of time to look into this, and indeed I was able
to reproduce the issue locally.

I'll send a patch ASAP, based on the the prototype patch I gave in the
previous reply.

Thanks for reporting,

Maxime