[U-Boot-Users] SCC Ethernet and "Linux crashes by early packets" ???

[Pantelis Antoniou <panto@intracom.gr>]

Wolfgang Denk wrote:

>In message <40757661.50905@imc-berlin.de> you wrote:
>
>>the CHANGELOG contains the lines
>>
>>* Make sure SCC Ethernet is always stopped by the time we boot Linux
>>   to avoid Linux crashes by early packets coming in.
>>
>>in "Changes for U-Boot 1.0.2".
>>
>>My two question:
>>
>>1.) How can I find out which changes in the CVS do excactly this?
>>
>
>Checking the CVS logs?
>
>Try: cvs diff -r1.3 -r1.4 post/ether.c 
>
>
>>2.) Do we need the same with 8xx FEC Ethernet?
>>
>
>I don't think so. Note that the ethernet interface was left in a non-
>stopped state by the POST code.  Normal  network  use  will  (should)
>correctly shut down the interface.
>
>
>
Actually we most certainly do. I was bitten by the same bug the past
week and have a patch ready; I'm just waiting for my other patches to
be included in order to sent it.

When we leave any ethernet on with DMA capability, there is a small
window of time before the new code reprograms the controller and stops
the DMA.

In the mean time if a packet is received (typically a broadcast) it
will write over in the physical memory where u-boot had placed it's
buffers. It's a crapshoot. Most of the times no-one will notice
since the possibility of actually overwritting something important is
very small.


>Best regards,
>
>Wolfgang Denk
>
>
Regards

Pantelis