ons 2009-01-07 klockan 07:52 -0500 skrev Jerry Van Baren:
Wolfgang Denk wrote:
Dear Ulf Samuelsson,
In message 1231282371.32308.276.camel@elrond.atmel.com you wrote:
It was tracked down to the autoconfiguration of the Ethernet PHY, so one of the PHYs ended up in 100 Mbps Half Duplex (think that was the switch) while the other PHY ended up in 100 MBps Full Duplex.
That would most probably be a bug in the U-Boot ethernet driver, then.
Best regards,
Wolfgang Denk
If auto-negotiation fails, the default is half duplex (10 or 100 - the speed can be discovered independent of the autonegotiation by the encoding).
Ulf's recollection that the switch was half duplex would indicate that the cheap switch did not autonegotiate properly, but u-boot did. This could be a u-boot bug (not setting up the negotiation properly), but more likely would be a switch problem (not handling the u-boot auto-neg options properly).
Don't remember all details, since it was 4 years ago. I talked to D-Link support and they claimed that the standard was to fall back to one of the options, if autonegotiation failed. The customer might have had a PHY without autonegotation which was hardwired to 100 Mbps full duplex.
With little communication, the packages were sent where this caused some problems.
gvb
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