Date: Fri, 04 Mar 2022 21:42:36 +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-Q6HQIGg0kI@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/>
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https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=3D262316 --- Comment #5 from Stefan E=C3=9Fer <se@FreeBSD.org> --- (In reply to J.R. Oldroyd from comment #3) I have located part of the IEEE 802.3 standard, specifically for Clause 37. it says in 37.1.4.4: ------------------------------------------------------------------- 37.1.4.4 User Configuration with Auto-Negotiation Rather than disabling Auto-Negotiation, the following behavior is suggested= in order to improve interoperability with other Auto-Negotiation devices. When= a device is configured for one specific mode of operation (e.g. 1000BASE-X Fu= ll Duplex), it is recommended to continue using Auto-Negotiation but only advertise the specifically selected ability or abilities. This can be done = by the Management agent only setting the bits in the advertisement registers t= hat correspond to the selected abilities. ------------------------------------------------------------------- I.e., a device manually set to operate in a fixed mode may signal the mode parameters to a partner, but it must not change its mode depending on what = the other side supports (even if this was required for a working data link). If manually set to full-duplex 1000base-X for example, the device may signal this setting and thus allows the other device to use a compatible configuration. But the manually configured device must not switch to some o= ther mode, even if the other interface does not support the manually configured mode. Modifying the manually set parameters is in violation of the standard, and = I'll close this PR again, unless there is proof of a standard clause that suppor= ts the change you are proposing. --=20 You are receiving this mail because: You are the assignee for the bug.=
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