Re: RCM4300 MTU Stuck at 16

Mike,

Thanks for reporting this with that added detail.  I was able to reproduce it on my end, and have pushed a fix up to GitHub.

https://github.com/digidotcom/DCRabbit_10/commit/18114a8d72d545b7ecca5581b37eb2d0dd520080

You can download the updated ASIX.LIB file using the following URL, and just replace the version in Dynamic C 10.72:

https://raw.githubusercontent.com/digidotcom/DCRabbit_10/18114a8d72d545b7ecca5581b37eb2d0dd520080/Lib/Rabbit4000/tcpip/ASIX.LIB

For those interested in knowing more, ip_print_ifs() calls ifmtu() in 10.72 instead of just pulling it from a field in the interface table (as it did in 10.66).  Because of a bug in ASIX.LIB, ifmtu() would get an uninitialized value from the stack instead of 0, the correct return value for unimplemented ioctl features.

This bug could have caused other networking-related errors on boards with an ASIX Ethernet controller.

-Tom


On Jan 29, 2016, at 9:16 AM, [email protected] [rabbit-semi] wrote:

> Hi Tom,
> 
> I applied the patch (TCP/IP.LIB) patch to DC 10.72 and re-ran the tests.
> The results were the same.
> 
> However when I used DC 10.66 then the problem went away.
> In other words, the value set by "ETH_MTU    1234" was correctly reported by   ip_print_ifs()  as;
> 
> Interface table:                                                                
>                                                                                 
> #  IP addr.        Mask            Up  Lnk Pwr Type MTU  Flags  Peer/router     
> -- --------------- --------------- --- --- --- ---- ---- ------ --------------- 
>  0 192.168.1.5     255.255.255.0   yes yes yes eth  1234 *      192.168.1.254  
>  
> MTU:1234      
> 
> So DC 10.66 works correctly with the RCM4300, while DC 10.72 does not.
> I don't have any of the intermediate versions between 10.66 and 10.72.
> 
> Regards,
> Mike
> 
>