Bug 238665 - muge(4) reduces the MTU when setting up a VLAN
Summary: muge(4) reduces the MTU when setting up a VLAN
Status: Closed FIXED
Alias: None
Product: Base System
Classification: Unclassified
Component: usb (show other bugs)
Version: CURRENT
Hardware: amd64 Any
: --- Affects Some People
Assignee: Ed Maste
URL:
Keywords: patch
Depends on:
Blocks:
 
Reported: 2019-06-17 12:36 UTC by iz-rpi03
Modified: 2019-10-08 21:43 UTC (History)
1 user (show)

See Also:


Attachments
One line patch to set IFCAP_VLAN_MTU capability. (407 bytes, patch)
2019-06-17 12:36 UTC, iz-rpi03
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Description iz-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 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