Bug 43277 - net/e1000e set mtu larger than 1500 fails
Summary: net/e1000e set mtu larger than 1500 fails
Status: RESOLVED INVALID
Alias: None
Product: Networking
Classification: Unclassified
Component: IPV4 (show other bugs)
Hardware: All Linux
: P1 normal
Assignee: Stephen Hemminger
URL:
Keywords:
Depends on:
Blocks:
 
Reported: 2012-05-22 18:13 UTC by Christer Ekholm
Modified: 2012-05-22 18:45 UTC (History)
0 users

See Also:
Kernel Version: 3.4
Subsystem:
Regression: Yes
Bisected commit-id:

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Description Christer Ekholm 2012-05-22 18:13:21 UTC 
In kernel 3.4 I can no longer use jumbo-frames with my e1000e network interface.

 $ sudo ip link set eth1 mtu 9000
 RTNETLINK answers: Invalid argument
 
Card-info (from kernel-log)

 e1000e 0000:05:00.1: eth1: (PCI Express:2.5GT/s:Width x4) 00:1b:78:59:84:25
 e1000e 0000:05:00.1: eth1: Intel(R) PRO/1000 Network Connection
 e1000e 0000:05:00.1: eth1: MAC: 0, PHY: 4, PBA No: D51930-003

I have bisected and found:

 70495a500d787c0c90a136acf454cb7d0eecd82e is the first bad commit
Comment 1 Christer Ekholm 2012-05-22 18:45:00 UTC 
Solved.

As the commitmessage actually says, and also kernel-message:

e1000e 0000:05:00.1: eth1: Jumbo frames cannot be enabled when both receive checksum offload and receive hashing are enabled.  Disable one of the receive offload features before enabling jumbos.

Setting rxhash to off works.

$ sudo ethtool -K eth1 rxhash off

$ sudo ip link set eth1 mtu 9000


-- 
 Christer
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