[Soekris] net4521 Phy Link

[Joseph Barstow]

Mike,
    Many thanks -- very simple and it seems to have done the trick.  I 
even had it compiled and installed already, just never found any 
documentation referring to the transceiver reset function.
    The 90-second boot time is unfortunate, and may come down if time 
remains before demo for optimization, in which case I may return to pick 
brains.  Thanks again for the help.

--Joe

Mike wrote:
> Joseph,
>
>    Good work, this is exactly an issue in the situation when a dhcp 
> server on a network is not booted yet before the clients come up and 
> begin requesting their addresses. Your stations then backoff and retry 
> later, resulting in a longer than comfortable period where they have 
> no addresses.
>
>    The tool you want is 'mii-tool' and you can use it thusly:
>
>    mii-tool -R eth0
>
>    Which will reset the transceiver on eth0, breaking link, allowing 
> the windows station to notice and begin re-acquiring the dhcp address.
>
>    In a larger deployment you may have to deal with this issue 
> differently. For example, a cisco switch like the 2924xl will take a 
> while to boot and during this time it's ethernets are effectively off, 
> so putting this switch in line with your soekris dhcp server would be 
> one strategy also.
>
>     Another idea is that 90 seconds to get your board booted and 
> serving dhcp is also a very long time. I have mine down to about 30 
> seconds - combonation of bios settings (fastboot = enabled and etc), 
> and a custom software roll. You may be able to make similar changes 
> for yours too.
>
> Mike-
>
>
> Joseph Barstow wrote:
>> Hi all,
>>     Short version: Is there a way to make 'ifconfig <dev> down' break 
>> phy link on the net4521's onboard Ethernet ports?
>>
>>     Long version: I'm working with a net4521 for a school project and 
>> have a small obstacle.  I have a Windows PC connected to each of the 
>> two Ethernet ports which are using DHCP for their IP address 
>> configurations.  The demo setup is such that the Windows PCs are 
>> fully booted before the net4521 powers on.  Herein lies the problem.
>>     My setup of Busybox Linux with kernel 2.6.19 takes approximately 
>> 90 seconds to boot from the CF card, but the Windows PCs begin 
>> sending DHCP requests as soon as the net4521 powers on and phy link 
>> comes up.  By the time dnsmasq is running to respond to the DHCP 
>> requests, the Windows PCs have given up and backed off to a slow 
>> retry.  All-in-all, despite the fact the net4521 only takes 90 
>> seconds to boot, they don't receive usable IP configurations for 
>> approximately 5 minutes.
>>     The best solution to this problem I can think of is to break phy 
>> link on both ports with an 'ifconfig <dev> down' command early in the 
>> boot sequence, and then bring it back up after dnsmasq is ready for 
>> DHCP requests, thus triggering the Windows PCs to ask for an address 
>> config.  However, ifconfig seems unable to break phy link on either 
>> Ethernet port.  Is there anything I can do about this?  Should I be 
>> using a specific driver module rather than the standard Ethernet 
>> support compiled into the 2.6.19 kernel?  Will Capone and his boys 
>> rule the streets of Chicago forever?
>>
>> Other vital information:
>> The context of the project is such that client PCs are expected to be 
>> varying and random.  I cannot use static configurations or alter the 
>> Windows DHCP timer -- I must attempt to fix this from the net4521's 
>> side.  Suggestions for accomplishing this without trying to break phy 
>> link are welcomed.
>>
>> Thanks guys,
>> Joe
>> ------------------------------------------------------------------------
>>
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