[ECOS] re: i82559 and FreeBSD stack

[Andrew Lunn <andrew dot lunn at ascom dot ch>]

Hi Gary

I spent an hour or two debugging the problem with the i82559 driver
and FreeBSD. I know have some more details, but no solution.

The problem occurs when loading and running the image using gdb over
Ethernet. If i load and run the same image using RedBoot:load command,
it works correctly. So its something to do with redboots stack
interacting with FreeBSD down in the ethernet driver.

I've also run the application with CYGDBG_IO_ETH_DRIVER_DEBUG enabled
and RedBoot force_console set. With this setup i get the IO ETH
drivers debug output on the serial port. This shows that TXs are
getting to this layer in the stack, but are not making it all the way
to the wire. 

Next i turned on INFRA_DEBUG. I should of done this earlier! There is
an assert on the first RX! In ResetRxRing(), the assertion 

          CYG_ASSERT( HAL_LE32TOC(link) == VIRT_TO_BUS(p_rfd), 
                      "rfd linked list broken" );

is happening. Its the 7th descriptor in the chain that is wrong.
Using __builtin_return_address i found out that ResetRxRing() is being
called from PacketRxReady(). For some reason the receive unit has
stopped.

Any ideas?

I will try to continue debugging tonight.

  Andrew

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