Date: Fri, 04 Mar 2022 21:45:00 +0000 From: bugzilla-noreply@freebsd.org To: bugs@FreeBSD.org Subject: [Bug 262316] em(4) does not autonegotiate when fixed media is set Message-ID: <bug-262316-227-rYwDjJENnC@https.bugs.freebsd.org/bugzilla/> In-Reply-To: <bug-262316-227@https.bugs.freebsd.org/bugzilla/> References: <bug-262316-227@https.bugs.freebsd.org/bugzilla/>
next in thread | previous in thread | raw e-mail | index | archive | help
https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=3D262316 --- Comment #6 from J.R. Oldroyd <fbsd@opal.com> --- (In reply to Stefan E=C3=9Fer from comment #4) To be clear, I would also oppose any commit that violates the Ethernet standard. I do now have the latest standard here, the 2018 version, in addition to my 2008 version. The standard does say that auto-negotiation is optional. And it defines half-duplex mode as the choice for when a peer does not respond to autoneg.= =20 This was to allow very old devices that did not have autoneg support to sti= ll work with newer devices that do have autoneg. But the statements: > the standard required a device to either participate in auto-negotiation = or to be manually configured. > A manually configured Ethernet device must ignore the auto-negotiation r= equest. are not correct by my reading. I do not see such statements. As I read it, a manually configured device may (in fact, it is highly recommended to) still participate in auto-negotiaton but it should limit wh= at capabilities it advertizes to just those that have been configured. That w= ay, the other end can match the configured capability if it has them. If not, autoneg will fail and the non-manually configured end is required to go to half-duplex which may result in a duplex mismatch. The standard requires participation in autoneg when manually configured for 1000base and that is already implemented in the em(4) driver. It is option= al but not prohibited for 100base and 10base. By my reading, it is "highly recommended" that a device participate in autoneg if it has the capability. --=20 You are receiving this mail because: You are the assignee for the bug.=
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?bug-262316-227-rYwDjJENnC>