Linux Kernel 2.6.14 Breaks Usbnet Xfer From Zaurus

[raybert]

pgas,

Thanks for the pointer; I missed those threads.  It works for me also.

It's not permanent though.  I was able to make it permanent by tweaking some of the /etc/hotplug scripts.

These are the changes I made, in case anyone wants to know:

/etc/hotplug/usbdnet.conf: add the line:

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MTU=576/etc/hotplug/net.agent: Look for the 'ifconfig' line under the "register)" and "usbd0)" cases (line ~74):

Code: [Select]

ifconfig usbd0 $IP netmask $NETMASKChange to:

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if [ -n "$MTU" ]; then SETMTU="mtu $MTU"; fi
ifconfig usbd0 $IP netmask $NETMASK $SETMTUIf you'd rather just hard-code it, you can just tack "mtu 576" onto the "ifconfig" line in net.agent.

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This solution begs a couple of questions though:

  1. WHY is this needed?  The Z has worked fine with its default MTU of 1500 for ages.

  2. Will the smaller MTU result in slower transfers?

Perhaps I'll try to dig up the code for the "hard MTU" patch that I wrote about earlier; it seems even more likely to be the culprit now...

~ray

[raybert]

FYI: The above solution also seems to work if applied on the PC-side.  Apparently, the fix works so long as you apply the MTU=576 to either side of the connection.

Those of us running Fedora/Red Hat or distros derived from them probably have a /etc/sysconfig/network-scripts/ifcfg-usb0 script to set-up the Z's usbnet connection.  I added MTU=576 to mine (after disabling my edits, described above, from the Z) and transfers don't hang.

This strikes me as a "better" solution.  IMO, the problem lies in Linux 2.6.14+ (and sounds like a bug to me) and so the fix should reside there as well.

~ray

[hvontres]

FYI: The above solution also seems to work if applied on the PC-side.  Apparently, the fix works so long as you apply the MTU=576 to either side of the connection.

Those of us running Fedora/Red Hat or distros derived from them probably have a /etc/sysconfig/network-scripts/ifcfg-usb0 script to set-up the Z's usbnet connection.  I added MTU=576 to mine (after disabling my edits, described above, from the Z) and transfers don't hang.

This strikes me as a "better" solution.  IMO, the problem lies in Linux 2.6.14+ (and sounds like a bug to me) and so the fix should reside there as well.

~ray
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Has anyone heard of a fix for this? I am trying to NAT my Z on FC4 and it seems I also need to set the MTU on my wireless card to 576 to get it to work....


Thanks,

Henry

[raybert]

Has anyone heard of a fix for this? I am trying to NAT my Z on FC4 and it seems I also need to set the MTU on my wireless card to 576 to get it to work....

Thanks,

Henry
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I haven't, but I haven't been looking either.  I haven't had a problem since installing the fix and I haven't had time to research it more.  I recently upgraded to 2.6.15-1.1833_FC4 with no trouble.

I thought this problem only effected usbnet though; I don't know why your wireless card is effected.  (I haven't used mine in a while; perhaps I'll have to check it.)

~ray