Bug 238665

Summary: muge(4) reduces the MTU when setting up a VLAN
Product: Base System Reporter: rz-rpi03
Component: usbAssignee: Ed Maste <emaste>
Status: Closed FIXED    
Severity: Affects Some People CC: emaste
Priority: --- Keywords: patch
Version: CURRENT   
Hardware: amd64   
OS: Any   
See Also: https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=205050
Attachments:
Description Flags
One line patch to set IFCAP_VLAN_MTU capability. none

Description rz-rpi03 2019-06-17 12:36:47 UTC 
Created attachment 205181 [details]
One line patch to set IFCAP_VLAN_MTU capability.

Do not drop the MTU from from 1500 to 1496 bytes when setting up a VLAN.
The chip is already configured for a maximum length of 1518 bytes.
See if_muge.c lines 1135ff at base r348020.

According to my tests adding IFCAP_VLAN_MTU to ifp->if_capabilities fixes this.

See also base r291953 for the same fix at the smsc(4) driver.
Comment 1 commit-hook freebsd_committer freebsd_triage 2019-07-02 16:44:13 UTC 
A commit references this bug:

Author: emaste
Date: Tue Jul  2 16:44:05 UTC 2019
New revision: 349602
URL: https://svnweb.freebsd.org/changeset/base/349602

Log:
  if_muge: set IFCAP_VLAN_MTU to maintain 1500 MTU with vlan use

  PR:		238665
  Submitted by:	Ralf <iz-rpi03@hs-karlsruhe.de>
  MFC after:	1 week

Changes:
  head/sys/dev/usb/net/if_muge.c
Comment 2 commit-hook freebsd_committer freebsd_triage 2020-03-08 18:23:27 UTC 
A commit references this bug:

Author: emaste
Date: Sun Mar  8 18:22:37 UTC 2020
New revision: 358762
URL: https://svnweb.freebsd.org/changeset/base/358762

Log:
  MFC r349602: if_muge: set IFCAP_VLAN_MTU to maintain 1500 MTU with vlan use

  PR:		238665
  Submitted by:	Ralf <iz-rpi03@hs-karlsruhe.de>

Changes:
_U  stable/12/
  stable/12/sys/dev/usb/net/if_muge.c