Hi Grant Thanks for the info, following your advise we've done the following:
We're using a PowerPC with a FEC, which is directly connected to an ethernet switch MAC using the MII. The MAC was set to full duplex, 100MBits, no flow control. The stock if_fec.c during fec_eth_reset, sets the Transmit control to "4+0", which is bit 29 - Full Duplex Enable in X_CNTRL. It also however configures fec->RxControl = RxControl_MII | RXControl_DRT; The DRT is "Disable receive on transmit". In the manual for the MPC852T it says to set DRT active for half-duplex, and disable for Full Duplex. When I remove the DRT being or'd in to the RxControl register, we get much better reliability. I'm now seeing a pause about once an hour, instead of once every couple of minutes. Does anyone know why fec->RxControl = RxControl_MII | RXControl_DRT contains the DRT portion when it looks like the fec driver is setting up for full duplex ? TIA Andy. On Mon, Oct 26, 2009 at 4:57 PM, Grant Edwards <[email protected]> wrote: > On 2009-10-26, andrew bell <[email protected]> wrote: > >> I?ve gone back to the nc_master / slave tests and monitored >> the throughput when connecting a PC to one of the boxes >> running eCos. Initially everything looked fine until I insert >> a switch between the PC and eCos box. >> >> With any switch between the PC / eCos box, there is poor >> performance when doing an RX test (PC -> eCos box), which >> shows lots of out of order delivery / delayed ACK / fast >> rexmit, and the throughout graph looks like a saw tooth. > > In my experience that's usually a sign of half/full duplex > mismatch between one of the PHYs and the Ethernet controller to > which it is attached. It could also be due to a mismatch > between a PHY and the switch, but you've got to try pretty hard > to make that happen. Can you try setting the switch ports to > various different duplicities? Or try a half-duplex hub/switch > instead of a full-duplex switch? > >> But hey, the PC?s running faster than the eCos box, so maybe >> this is to be expected. > > Nope. > > -- > Grant > > > > -- > Before posting, please read the FAQ: http://ecos.sourceware.org/fom/ecos > and search the list archive: http://ecos.sourceware.org/ml/ecos-discuss > > -- Before posting, please read the FAQ: http://ecos.sourceware.org/fom/ecos and search the list archive: http://ecos.sourceware.org/ml/ecos-discuss
