From: Russell King - ARM Linux admin <linux@armlinux.org.uk>
To: Martin Rowe <martin.p.rowe@gmail.com>
Cc: Andrew Lunn <andrew@lunn.ch>,
netdev@vger.kernel.org, davem@davemloft.net,
vivien.didelot@gmail.com
Subject: Re: bug: net: dsa: mv88e6xxx: unable to tx or rx with Clearfog GT 8K (with git bisect)
Date: Fri, 17 Jul 2020 19:51:19 +0100 [thread overview]
Message-ID: <20200717185119.GL1551@shell.armlinux.org.uk> (raw)
In-Reply-To: <CAOAjy5RNz8mGi4XjP_8x-aZo5VhXRFF446R7NgcQGEKWVpUV1Q@mail.gmail.com>
On Fri, Jul 17, 2020 at 12:50:07PM +0000, Martin Rowe wrote:
> On Fri, 17 Jul 2020 at 09:22, Russell King - ARM Linux admin
> <linux@armlinux.org.uk> wrote:
> > The key file is /sys/kernel/debug/mv88e6xxx.0/regs - please send the
> > contents of that file.
>
> $ cat regs.broken
> GLOBAL GLOBAL2 SERDES 0 1 2 3 4 5
> 0: c800 0 ffff 9e07 9e4f 100f 100f 9e4f 170b
> 1: 0 803e ffff 3 3 3 3 3 201f
^^^^
This is where the problem is.
> 1: 0 803e ffff 3 3 3 3 3 203f
^^^^
In the broken case, the link is forced down, in the working case, the
link is forced up.
What seems to be happening is:
dsa_port_link_register_of() gets called, and we do this:
phy_np = of_parse_phandle(dp->dn, "phy-handle", 0);
if (of_phy_is_fixed_link(dp->dn) || phy_np) {
if (ds->ops->phylink_mac_link_down)
ds->ops->phylink_mac_link_down(ds, port,
MLO_AN_FIXED, PHY_INTERFACE_MODE_NA);
return dsa_port_phylink_register(dp);
which forces the link down, and for some reason the link never comes
back up.
One of the issues here is of_phy_is_fixed_link() - it is dangerous.
The function name leads you astray - it suggests that if it returns
true, then you have a fixed link, but it also returns true of you
have managed!="auto" in DT, so it's actually fixed-or-inband-link.
Andrew, any thoughts?
I think it's looking more and more like we need my phylink hack to
grab the "defaults" for the port on phylink_start() to allow DSA to
work sanely with phylink, so that phylink can have the complete
information about the CPU port at all times.
--
RMK's Patch system: https://www.armlinux.org.uk/developer/patches/
FTTP is here! 40Mbps down 10Mbps up. Decent connectivity at last!
next prev parent reply other threads:[~2020-07-17 18:51 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-11 13:50 bug: net: dsa: mv88e6xxx: unable to tx or rx with Clearfog GT 8K (with git bisect) Martin Rowe
2020-07-11 16:23 ` Andrew Lunn
2020-07-11 19:22 ` Russell King - ARM Linux admin
2020-07-12 13:00 ` Martin Rowe
2020-07-12 13:25 ` Russell King - ARM Linux admin
2020-07-17 5:56 ` Martin Rowe
2020-07-17 9:21 ` Russell King - ARM Linux admin
2020-07-17 12:50 ` Martin Rowe
2020-07-17 18:51 ` Russell King - ARM Linux admin [this message]
2020-07-17 19:42 ` Andrew Lunn
2020-07-17 21:26 ` Russell King - ARM Linux admin
2020-07-18 2:37 ` Martin Rowe
2020-07-18 8:50 ` Russell King - ARM Linux admin
2020-07-18 9:43 ` Martin Rowe
2020-07-18 10:12 ` Russell King - ARM Linux admin
2020-07-18 11:21 ` Martin Rowe
2020-07-18 11:26 ` Russell King - ARM Linux admin
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