Intel 82550 Pro/100 Ethernet and TSO troubles

YongHyeon PYUN pyunyh at gmail.com
Wed Dec 14 20:00:22 UTC 2011


On Wed, Dec 14, 2011 at 08:33:36PM +0100, Andrea Venturoli wrote:
> Hello.
> 
> I recently installed 8.2 with the following card:
> 
> > dmesg
> > ...
> >fxp0: <Intel 82550 Pro/100 Ethernet> port 0xdc00-0xdc3f mem 
> >0xfebfb000-0xfebfbfff,0xfebc0000-0xfebdffff irq 20 at device 5.0 on pci4
> > ...
> > pciconv -lv
> > ...
> >fxp0 at pci0:4:5:0:        class=0x020000 card=0x00408086 chip=0x12298086 
> >rev=0x0c hdr=0x00
> >    vendor     = 'Intel Corporation'
> >    device     = '82550/1/7/8/9 EtherExpress PRO/100(B) Ethernet Adapter'
> >    class      = network
> >    subclass   = ethernet
> > ...
> 
> I had weird problems, especially due to ICMP/fragmentation/MTU/... issues.
> After hours spent in debugging, I noticed  tcpdump showing ICMP packets 
> with wrong checksums and that TSO4 was enabled.
> "ifconfig fxp0 -tso" seemed to solve everything.
> 
> 
> Don't know if it's a bug in the card, in the driver or what...
> Maybe it shouldn't be enabled by default?
> 

AFAIK the firmware of controller has no known TSO issue so it
indicates a bug in driver.
What makes me wonder is ICMP ECHO packet should not be affected by
TSO and I have no clue at this moment. (Here, I assume you've
captured packets on receiver side since bpf sees packets before
hardware computes checksum.)  If you have a reliable way that
reproduces the issue, let me know.

> 
> 
> 
> I also have fxp1:
> > dmesg
> > ...
> >fxp1: <Intel 82559 Pro/100 Ethernet> port 0xd880-0xd8bf mem 0xfebfa
> >000-0xfebfafff,0xfea00000-0xfeafffff irq 21 at device 6.0 on pci4
> >...
> >pciconv -lv
> >...
> >fxp1 at pci0:4:6:0:        class=0x020000 card=0x000c8086 chip=0x12298086 
> >rev=0x08 hdr=0x00
> >    vendor     = 'Intel Corporation'
> >    device     = '82550/1/7/8/9 EtherExpress PRO/100(B) Ethernet Adapter'
> >    class      = network
> >    subclass   = ethernet
> > ...
> 
> TSO was not enabled on this by default.
> 

TSO is available only on i82550/i82551.

> 
> 
> 
> Feel free to ask, in case you need any further info.
> 
>  bye
> 	av.


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