Subject: Re: Clause 73 and USXGMII

From: Russell King - ARM Linux admin <[email-masked]>
Date: Thu, 8 Aug 2019 09:26:26 +0100

Hi,

Have you tried enabling debug mode in phylink (add #define DEBUG at the
top of the file) ?

Thanks.

On Thu, Aug 08, 2019 at 08:17:29AM +0000, Jose Abreu wrote:
> ++ PHY Experts
> 
> From: Jose Abreu <[email-masked]>
> Date: Aug/07/2019, 16:46:23 (UTC+00:00)
> 
> > Hello,
> > 
> > I've some sample code for Clause 73 support using Synopsys based XPCS 
> > but I would like to clarify some things that I noticed.
> > 
> > I'm using USXGMII as interface and a single SERDES that operates at 10G 
> > rate but MAC side is working at 2.5G. Maximum available bandwidth is 
> > therefore 2.5Gbps.
> > 
> > So, I configure USXGMII for 2.5G mode and it works but if I try to limit 
> > the autoneg abilities to 2.5G max then it never finishes:
> > # ethtool enp4s0
> > Settings for enp4s0:
> > 	Supported ports: [ ]
> > 	Supported link modes:   1000baseKX/Full 
> > 	                        2500baseX/Full 
> > 	Supported pause frame use: Symmetric Receive-only
> > 	Supports auto-negotiation: Yes
> > 	Supported FEC modes: Not reported
> > 	Advertised link modes:  1000baseKX/Full 
> > 	                        2500baseX/Full 
> > 	Advertised pause frame use: Symmetric Receive-only
> > 	Advertised auto-negotiation: Yes
> > 	Advertised FEC modes: Not reported
> > 	Speed: Unknown!
> > 	Duplex: Unknown! (255)
> > 	Port: MII
> > 	PHYAD: 0
> > 	Transceiver: internal
> > 	Auto-negotiation: on
> > 	Supports Wake-on: ug
> > 	Wake-on: d
> > 	Current message level: 0x0000003f (63)
> > 			       drv probe link timer ifdown ifup
> > 	Link detected: no
> > 
> > When I do not limit autoneg and I say that maximum limit is 10G then I 
> > get Link Up and autoneg finishes with this outcome:
> > # ethtool enp4s0
> > Settings for enp4s0:
> > 	Supported ports: [ ]
> > 	Supported link modes:   1000baseKX/Full 
> > 	                        2500baseX/Full 
> > 	                        10000baseKX4/Full 
> > 	                        10000baseKR/Full 
> > 	Supported pause frame use: Symmetric Receive-only
> > 	Supports auto-negotiation: Yes
> > 	Supported FEC modes: Not reported
> > 	Advertised link modes:  1000baseKX/Full 
> > 	                        2500baseX/Full 
> > 	                        10000baseKX4/Full 
> > 	                        10000baseKR/Full 
> > 	Advertised pause frame use: Symmetric Receive-only
> > 	Advertised auto-negotiation: Yes
> > 	Advertised FEC modes: Not reported
> > 	Link partner advertised link modes:  1000baseKX/Full 
> > 	                                     2500baseX/Full 
> > 	                                     10000baseKX4/Full 
> > 	                                     10000baseKR/Full 
> > 	Link partner advertised pause frame use: Symmetric Receive-only
> > 	Link partner advertised auto-negotiation: Yes
> > 	Link partner advertised FEC modes: Not reported
> > 	Speed: 2500Mb/s
> > 	Duplex: Full
> > 	Port: MII <- Never mind this, it's a SW issue
> > 	PHYAD: 0
> > 	Transceiver: internal
> > 	Auto-negotiation: on
> > 	Supports Wake-on: ug
> > 	Wake-on: d
> > 	Current message level: 0x0000003f (63)
> > 			       drv probe link timer ifdown ifup
> > 	Link detected: yes
> > 
> > I was expecting that, as MAC side is limited to 2.5G, I should set in 
> > phylink the correct capabilities and then outcome of autoneg would only 
> > have up to 2.5G modes. Am I wrong ?
> > 
> > ---
> > Thanks,
> > Jose Miguel Abreu
> 
> 
> ---
> Thanks,
> Jose Miguel Abreu
> 

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