From: Doug Berger <opendmb@gmail.com>
To: "Wang, Xiaolei" <Xiaolei.Wang@windriver.com>,
"f.fainelli@gmail.com" <f.fainelli@gmail.com>,
"bcm-kernel-feedback-list@broadcom.com"
<bcm-kernel-feedback-list@broadcom.com>,
Andrew Lunn <andrew@lunn.ch>,
Heiner Kallweit <hkallweit1@gmail.com>,
Russell King <linux@armlinux.org.uk>,
"David S. Miller" <davem@davemloft.net>,
Eric Dumazet <edumazet@google.com>,
Jakub Kicinski <kuba@kernel.org>,
"pabeni@redhat.com" <pabeni@redhat.com>,
"richardcochran@gmail.com" <richardcochran@gmail.com>
Cc: "netdev@vger.kernel.org" <netdev@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: BCM54220: After the BCM54220 closes the auto-negotiation, the configuration forces the 1000M network port to be linked down all the time.
Date: Tue, 21 Feb 2023 10:44:44 -0800 [thread overview]
Message-ID: <ae617cad-63dc-333f-c4c4-5266de88e4f8@gmail.com> (raw)
In-Reply-To: <MW5PR11MB5764F9734ACFED2EF390DFF795A19@MW5PR11MB5764.namprd11.prod.outlook.com>
On 2/17/2023 12:06 AM, Wang, Xiaolei wrote:
> hi
>
> When I use the nxp-imx7 board, eth0 is connected to the PC, eth0 is turned off the auto-negotiation mode, and the configuration is forced to 10M, 100M, 1000M. When configured to force 1000M，
> The link status of phy status reg(0x1) is always 0, and the chip of phy is BCM54220, but I did not find the relevant datasheet on BCM official website, does anyone have any suggestions or the datasheet of BCM54220?
>
> thanks
> xiaolei
>
It is my understanding that the 1000BASE-T PHY requires peers to take on
asymmetric roles and that establishment of these roles requires
negotiation which occurs during auto-negotiation. Some PHYs may allow
manual programming of these roles, but it is not standardized and tools
like ethtool do not support manual specification of such details.
Therefore manual configuration of a 1000BASE-T link cannot be assumed to
work. If you want to "force" a gigabit link you should keep
auto-negotiation on and only advertise support for the speed you want.
Regards,
Doug
next prev parent reply other threads:[~2023-02-21 18:46 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <MW5PR11MB5764F9734ACFED2EF390DFF795A19@MW5PR11MB5764.namprd11.prod.outlook.com>
2023-02-17 17:13 ` BCM54220: After the BCM54220 closes the auto-negotiation, the configuration forces the 1000M network port to be linked down all the time Florian Fainelli
2023-02-21 8:04 ` wangxiaolei
2023-02-21 18:44 ` Doug Berger [this message]
2023-02-21 19:41 ` Andrew Lunn
2023-02-21 19:53 ` Doug Berger
2023-02-21 21:51 ` Doug Berger
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