Hello All, just figured out that one issue with this PHY is the "Energy Detect Power-Down" feature. This actually powers down the transceiver, and waits for a suitable signal to power-up again (see datasheet of the PHY).
This works only on gigabit switches somewhat reliable, but on 10/100 MBit switches, it usually doesn't come up again. Furthermore, that may be even enforced by a schematic issue: Tx and Rx are not connected as specified by the PHY (Tx should go to pin 1 and 2, RX to the others). This is not a big deal as MDI-X fixes this, but this might be the root cause that the Energy Detect algorithm doesn't work on 10/100. However, we just disabled this feature by removing the enabling lines from the smsc.c driver within smsc_phy_config_init(). Maybe this helps! Am Montag, 10. Juni 2013 17:23:32 UTC+2 schrieb necron...@gmail.com: > > I'm having a strange problem with my new BeagleBone black: I can transmit > packets from the Ethernet port but not receive them. > > When using DHCP, I can see (via a sniffer) the DHCP DISCOVER packet sent > from the 'bone (via a network sniffer). I can see my DHCP server (dnsmasq > 2.59 on stock Ubuntu 12.04 LTS 64-bit server) send a DHCP OFFER. But the > 'bone acts like it never hears the offer; it just sends out more DISCOVERs > at intervals. (The same DHCP server is working fine for dozens of clients > from various vendors. There are plenty of leases left in the pool.) > > If I set a static address and try to ping something, I see the 'bone send > an ARP who-has, I see the target reply with an ARP is-at, but the 'bone > just keeps ARP-ing, and never gets an entry in its ARP table. > > In the ifconfig output, the eth0 interface shows 0 packets received and 0 > errors. (The number transmitted is non-0.) Nothing suspicious in the dmesg > output that I can see. > > I've repeated the tests with both the latest Angstrom and with Ubuntu > booted off an SD card. Same results. I've tried two different cables, and > two different ports on two different Ethernet switches from different > vendors. (All ports and cables verified to work fine with my laptop.) > > One interesting observation: the port seems to always end up on 10Mbps, > even when plugged into 100Mbps- (or gigabit-) capable ports. So, it looks > like autonegotiation isn't working either. > > I'm running on a 2A 5.00V regulated bench supply, and the DC looks clean > on the o-scope. > > Other 'bone functions (USB host, USB target, HDMI, LEDs) all seem to work > fine. > > I'm starting to suspect a hardware problem (busted PHY or magnetics; > incomplete or bridged trace). > > Any suggestions for stuff I should try before I RMA the poor little guy? > (I'm an experienced Linux user and reasonably competent electronics > hobbyist, if that matters.) > -- For more options, visit http://beagleboard.org/discuss --- You received this message because you are subscribed to the Google Groups "BeagleBoard" group. To unsubscribe from this group and stop receiving emails from it, send an email to beagleboard+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
