Bug 205050 - VLAN_MTU required by smsc driver
Summary: VLAN_MTU required by smsc driver
Status: Closed FIXED
Alias: None
Product: Base System
Classification: Unclassified
Component: usb (show other bugs)
Version: CURRENT
Hardware: arm Any
: --- Affects Only Me
Assignee: freebsd-usb (Nobody)
URL:
Keywords: patch
Depends on:
Blocks:
 
Reported: 2015-12-06 04:42 UTC by rpp
Modified: 2019-06-18 19:28 UTC (History)
1 user (show)

See Also:

Attachments
patch to sys/dev/usb/net/if_smsc.c (546 bytes, patch)
2015-12-06 04:42 UTC, rpp 		no flags Details | Diff
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Description rpp 2015-12-06 04:42:21 UTC 
Created attachment 163881 [details]
patch to sys/dev/usb/net/if_smsc.c

When setting up VLANs on a Raspberry Pi ethernet port, the MTU drops from 1500 to 1496 bytes. The MTU should remain at 1500, extending the frame size as per IEEE 802.3.  Adding IFCAP_VLAN_MTU to the if_capabilities field in the smsc driver solves the problem.  The datasheet for the LAN9512 chip, section 3.2.3 states that the chip supports the extended frame.  Trivial patch attached.
Comment 1 commit-hook freebsd_committer freebsd_triage 2015-12-07 18:56:27 UTC 
A commit references this bug:

Author: hselasky
Date: Mon Dec  7 18:55:33 UTC 2015
New revision: 291953
URL: https://svnweb.freebsd.org/changeset/base/291953

Log:
  When setting up VLANs on a Raspberry Pi ethernet port, the MTU drops
  from 1500 to 1496 bytes. The MTU should remain at 1500, extending the
  frame size as per IEEE 802.3. Adding IFCAP_VLAN_MTU to the
  if_capabilities field in the smsc driver solves the problem.  The
  datasheet for the LAN9512 chip, section 3.2.3 states that the chip
  supports the extended frame.

  Submitted by:	rpp@ci.com.au
  MFC after:	1 week
  PR:		205050

Changes:
  head/sys/dev/usb/net/if_smsc.c
Comment 2 commit-hook freebsd_committer freebsd_triage 2015-12-14 09:46:51 UTC 
A commit references this bug:

Author: hselasky
Date: Mon Dec 14 09:46:47 UTC 2015
New revision: 292185
URL: https://svnweb.freebsd.org/changeset/base/292185

Log:
  MFC r291953:
  When setting up VLANs on a Raspberry Pi ethernet port, the MTU drops
  from 1500 to 1496 bytes. The MTU should remain at 1500, extending the
  frame size as per IEEE 802.3. Adding IFCAP_VLAN_MTU to the
  if_capabilities field in the smsc driver solves the problem.  The
  datasheet for the LAN9512 chip, section 3.2.3 states that the chip
  supports the extended frame.

  Submitted by:	rpp@ci.com.au
  PR:		205050

Changes:
_U  stable/10/
  stable/10/sys/dev/usb/net/if_smsc.c