> -----Original Message-----
> From: Jakub Kicinski <k...@kernel.org>
> Sent: Monday, October 12, 2020 6:58 PM
> To: Danielle Ratson <daniel...@nvidia.com>
> Cc: Ido Schimmel <ido...@idosch.org>; netdev@vger.kernel.org;
> da...@davemloft.net; Jiri Pirko <j...@nvidia.com>; and...@lunn.ch;
> f.faine...@gmail.com; mkube...@suse.cz; mlxsw <ml...@nvidia.com>; Ido
> Schimmel <ido...@nvidia.com>; johan...@sipsolutions.net
> Subject: Re: [PATCH net-next 1/6] ethtool: Extend link modes settings uAPI
> with lanes
>
> On Mon, 12 Oct 2020 15:33:45 +0000 Danielle Ratson wrote:
> > > What's the use for this in practical terms? Isn't the lane count
> > > basically implied by the module that gets plugged in?
> >
> > The use is to enable the user to decide how to achieve a certain speed.
> > For example, if he wants to get 100G and the port has 4 lanes, the
> > speed can be achieved it using both 2 lanes of 50G and 4 lanes of 25G,
> > as a port with 4 lanes width can work in 2 lanes mode with double
> > speed each. So, by specifying "lanes 2" he will achieve 100G using 2
> > lanes of 50G.
>
> Can you give a concrete example of serdes capabilities of the port, what SFP
> gets plugged in and what configuration user wants to select?
Example:
- swp1 is a 200G port with 4 lanes.
- QSFP28 is plugged in.
- The user wants to select configuration of 100G speed using 2 lanes, 50G each.
$ ethtool swp1
Settings for swp1:
Supported ports: [ FIBRE Backplane ]
Supported link modes: 1000baseT/Full
10000baseT/Full
1000baseKX/Full
10000baseKR/Full
10000baseR_FEC
40000baseKR4/Full
40000baseCR4/Full
40000baseSR4/Full
40000baseLR4/Full
25000baseCR/Full
25000baseKR/Full
25000baseSR/Full
50000baseCR2/Full
50000baseKR2/Full
100000baseKR4/Full
100000baseSR4/Full
100000baseCR4/Full
100000baseLR4_ER4/Full
50000baseSR2/Full
10000baseCR/Full
10000baseSR/Full
10000baseLR/Full
10000baseER/Full
50000baseKR/Full
50000baseSR/Full
50000baseCR/Full
50000baseLR_ER_FR/Full
50000baseDR/Full
100000baseKR2/Full
100000baseSR2/Full
100000baseCR2/Full
100000baseLR2_ER2_FR2/Full
100000baseDR2/Full
200000baseKR4/Full
200000baseSR4/Full
200000baseLR4_ER4_FR4/Full
200000baseDR4/Full
200000baseCR4/Full
Advertised link modes: 1000baseT/Full
10000baseT/Full
1000baseKX/Full
10000baseKR/Full
10000baseR_FEC
40000baseKR4/Full
40000baseCR4/Full
40000baseSR4/Full
40000baseLR4/Full
25000baseCR/Full
25000baseKR/Full
25000baseSR/Full
50000baseCR2/Full
50000baseKR2/Full
100000baseKR4/Full
100000baseSR4/Full
100000baseCR4/Full
100000baseLR4_ER4/Full
50000baseSR2/Full
10000baseCR/Full
10000baseSR/Full
10000baseLR/Full
10000baseER/Full
50000baseKR/Full
50000baseSR/Full
50000baseCR/Full
50000baseLR_ER_FR/Full
50000baseDR/Full
100000baseKR2/Full
100000baseSR2/Full
100000baseCR2/Full
100000baseLR2_ER2_FR2/Full
100000baseDR2/Full
200000baseKR4/Full
200000baseSR4/Full
200000baseLR4_ER4_FR4/Full
200000baseDR4/Full
200000baseCR4/Full
Advertised pause frame use: No
Advertised auto-negotiation: Yes
Advertised FEC modes: Not reported
Speed: Unknown!
Lanes: Unknown!
Duplex: Unknown! (255)
Auto-negotiation: on
Port: Direct Attach Copper
PHYAD: 0
Transceiver: internal
Link detected: no
$ ethtool -s swp1 speed 100000 lanes 2
$ ethtool swp1
Settings for swp1:
Supported ports: [ FIBRE Backplane ]
Supported link modes: 1000baseT/Full
10000baseT/Full
1000baseKX/Full
10000baseKR/Full
10000baseR_FEC
40000baseKR4/Full
40000baseCR4/Full
40000baseSR4/Full
40000baseLR4/Full
25000baseCR/Full
25000baseKR/Full
25000baseSR/Full
50000baseCR2/Full
50000baseKR2/Full
100000baseKR4/Full
100000baseSR4/Full
100000baseCR4/Full
100000baseLR4_ER4/Full
50000baseSR2/Full
10000baseCR/Full
10000baseSR/Full
10000baseLR/Full
10000baseER/Full
50000baseKR/Full
50000baseSR/Full
50000baseCR/Full
50000baseLR_ER_FR/Full
50000baseDR/Full
100000baseKR2/Full
100000baseSR2/Full
100000baseCR2/Full
100000baseLR2_ER2_FR2/Full
100000baseDR2/Full
200000baseKR4/Full
200000baseSR4/Full
200000baseLR4_ER4_FR4/Full
200000baseDR4/Full
200000baseCR4/Full
Supported pause frame use: Symmetric Receive-only
Supports auto-negotiation: Yes
Supported FEC modes: Not reported
Advertised link modes: 100000baseKR2/Full
100000baseSR2/Full
100000baseCR2/Full
100000baseLR2_ER2_FR2/Full
100000baseDR2/Full
Advertised pause frame use: No
Advertised auto-negotiation: Yes
Advertised FEC modes: Not reported
- [PATCH net-next 0/6] Support setting lanes via ethtool Ido Schimmel
- [PATCH net-next 4/6] mlxsw: ethtool: Add support for ... Ido Schimmel
- [PATCH net-next 2/6] ethtool: Expose the number of la... Ido Schimmel
- [PATCH net-next 3/6] mlxsw: ethtool: Remove max lanes... Ido Schimmel
- [PATCH net-next 1/6] ethtool: Extend link modes setti... Ido Schimmel
- Re: [PATCH net-next 1/6] ethtool: Extend link mod... Jakub Kicinski
- RE: [PATCH net-next 1/6] ethtool: Extend link... Danielle Ratson
- Re: [PATCH net-next 1/6] ethtool: Extend ... Jakub Kicinski
- RE: [PATCH net-next 1/6] ethtool: Ex... Danielle Ratson
- Re: [PATCH net-next 1/6] ethtool... Jakub Kicinski
- Re: [PATCH net-next 1/6] ethtool... Andrew Lunn
- RE: [PATCH net-next 1/6] eth... Danielle Ratson
- Re: [PATCH net-next 1/6] eth... Michal Kubecek
- Re: [PATCH net-next 1/6] eth... Jiri Pirko
- Re: [PATCH net-next 1/6] eth... Michal Kubecek
- RE: [PATCH net-next 1/6] eth... Danielle Ratson
- Re: [PATCH net-next 1/6] eth... Michal Kubecek
- RE: [PATCH net-next 1/6] eth... Danielle Ratson
- Re: [PATCH net-next 1/6] eth... Michal Kubecek
