Messages in this thread | | | Date | Mon, 21 May 2001 22:12:53 +1000 | From | Andrew Morton <> | Subject | Re: 3c905C-TX [Fast Etherlink] problem ... |
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Robert Vojta wrote: > > > This is a `transamit reclaim' error. It is almost always > > caused by this host being in half-duplex mode, and another > > host on the network being in full-duplex mode. > > Hi, > I tried to force this to be in fullduplex mode by options=0x204 (0x200 + 0x4) > and it works fine now.
mm.. It _should_ autonegotiate. Perhaps the device at the other end is old or not very good.
> Please, can you send me some points to the documentation > where I can read more info about 'transamit reclaim' error and why this > happens, etc ...
http://www.scyld.com/network/vortex.html is the official place. It doesn't tell you much.
vortex.txt has a pointer to 3com's documentation. Heavy going.
When the NIC is running in full-duplex mode it *assumes* that once (by default) 128 bytes of a frame have gone onto the wire, the remainder of the frame will be sent without any collisions. This assumption allows it to reuse part on the on-board memory - it transfers more data from the host into the place where the currently-transmitting frame used to reside.
If another host then comes along and generates a collision this late into the frame, the NIC detects it but cannot back off and retransmit the frame as it would normally do. Because the frame's memory has been "reclaimed". All it can do is raise an interrupt and complain.
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