It was <2020-10-14 śro 23:04>, when Russell King - ARM Linux admin wrote: > On Wed, Oct 14, 2020 at 04:39:47PM +0200, Lukasz Stelmach wrote: >> It was <2020-10-14 śro 14:32>, when Russell King - ARM Linux admin wrote: >> > In any case, the mii.c code does fill in the advertising mask even >> > when autoneg is disabled, because, rightly or wrongly, the advertising >> > mask contains more than just the link modes, it includes the >> > interface(s) as well. Your change means phylib no longer reports the >> > interface modes which is at odds with the mii.c code. >> >> I am afraid you are wrong. There is a rather big if()[1], which >> depending on AN beeing enabled fills more or less information. Yes this >> if() looks like it has been yanked from mii_ethtool_gset(). When >> advertising is converted and copied to cmd->link_modes.advertising at >> the end of mii_ethtool_get_link_ksettings() it is 0[2] if autonegotiation >> is disabled. >> >> [1] >> https://protect2.fireeye.com/v1/url?k=d1d33944-8c07852c-d1d2b20b-0cc47a3356b2-cede44db8a43e7c3&q=1&e=d1dea895-d1df-46b9-8413-ac329b0bbfa7&u=https%3A%2F%2Felixir.bootlin.com%2Flinux%2Fv5.9%2Fsource%2Fdrivers%2Fnet%2Fmii.c%23L174 >> [2] >> https://protect2.fireeye.com/v1/url?k=c840e942-9594552a-c841620d-0cc47a3356b2-510c0749446ea7df&q=1&e=d1dea895-d1df-46b9-8413-ac329b0bbfa7&u=https%3A%2F%2Felixir.bootlin.com%2Flinux%2Fv5.9%2Fsource%2Fdrivers%2Fnet%2Fmii.c%23L215 > > I'm very sorry, but I have to disagree. I'll quote the code here: > > advertising = ADVERTISED_TP | ADVERTISED_MII; > > // This is your big if() > if (bmcr & BMCR_ANENABLE) { > advertising |= ADVERTISED_Autoneg; > ... > } else { > ... > } > > ethtool_convert_legacy_u32_to_link_mode(cmd->link_modes.advertising, > advertising); > > So, when AN is disabled, we still end up with TP and MII in the > advertised link modes. I call TP and MII "interface modes" above > to separate them from the "link modes" that describe the speed and > duplex etc.
Yes.
> Note that only lp_advertising is zeroed in the "else" clause of
> the above "if" statement - advertising remains as-is with TP and MII
> set.
Yes.
> Your patch, on the other hand, merely avoids setting anything in
> cmd->link_modes.advertising, which means we do not end up with the
> "interface modes".
>
> I hope that this helps you see my point.
Yes.
Thanks.
tl;dr: v2 is coming.
Let's take a look at what ethtool prints. With AN enabled
--8<---------------cut here---------------start------------->8---
Settings for enx00249b14f06e:
Supported ports: [ TP MII ]
Supported link modes: 10baseT/Half 10baseT/Full
100baseT/Half 100baseT/Full
1000baseT/Half 1000baseT/Full
Supported pause frame use: No
Supports auto-negotiation: Yes
Supported FEC modes: Not reported
Advertised link modes: 10baseT/Half 10baseT/Full
100baseT/Half 100baseT/Full
1000baseT/Full
Advertised pause frame use: Symmetric
Advertised auto-negotiation: Yes
[...]
Link detected: yes
--8<---------------cut here---------------end--------------->8---
with AN disabled
--8<---------------cut here---------------start------------->8---
Settings for enx00249b14f06e:
Supported ports: [ TP MII ]
Supported link modes: 10baseT/Half 10baseT/Full
100baseT/Half 100baseT/Full
1000baseT/Half 1000baseT/Full
Supported pause frame use: No
Supports auto-negotiation: Yes
Supported FEC modes: Not reported
Advertised link modes: Not reported
Advertised pause frame use: No
Advertised auto-negotiation: No
[...]
Link detected: yes
--8<---------------cut here---------------end--------------->8---
The driver is ax88179_178a which calls mii_ethtool_get_link_ksettings()
The first line that differs is "Advertised link modes". Apparently[1]
ethtool does not consider ADVERTISED_TP and ADVERTISED_MII as
interesting modes. Indeed I should add an else clause to clear
cmd->link_modes.advertising (and lp_advertising) and set only
ETHTOOL_LINK_MODE_TP_BIT and ETHTOOL_LINK_MODE_MII_BIT.
[1]
https://git.kernel.org/pub/scm/network/ethtool/ethtool.git/tree/ethtool.c?h=v5.8#n656
--
Łukasz Stelmach
Samsung R&D Institute Poland
Samsung Electronics
signature.asc
Description: PGP signature
