[ECOS] Re: connect ethernet cable at run-time

Jonathan Larmour jifl@jifvik.org
Fri Sep 25 00:11:00 GMT 2009


Grant Edwards wrote:
> On 2009-09-24, Jonathan Larmour <jifl@jifvik.org> wrote:
> 
>>Grant Edwards wrote:
>>
>>>On 2009-09-24, Lars Dahlin <haraxidix@gmail.com> wrote:
>>>
>>>
>>>>I want to be able to connect the ethernet cable and it
>>>>shouldn't be necesary to restart ecos.
> 
> 
> [...]
> 
> 
>>>Again, I've never seen that.  We connect/disconnect Ethernet
>>>cables all the time, and never have to restart anything.  
>>>
>>>We do have code in our Ethernet drivers that makes sure that
>>>the Ethernet MAC duplex setting is changed to match the PHY's
>>>negotiation results when a cable is plugged in, but I don't
>>>think that has anything to do with what you're talking about.
>>
>>I think the issue may be that if you start the device with it 
>>disconnected, nothing _automatically_ will bring the interface
>>up using BOOTP/DHCP.
> 
> 
> If one calls init_all_network_interfaces() before the Ethernet
> link is up does the DHCP code give up and terminate?  IOW,
> doesn't the DHCP client code retry if it doesn't get a
> response?  That seems a bit odd.

I don't believe it does retry at present.

See for example in dhcp_prot.c that do_dhcp() calls no_lease(), whicih 
disables and deletes the alarm. Without that the needs_attention semaphore 
is not posted and the dhcp management thread gets stuck waiting on it. 
That's my belief anyway.

Jifl
-- 
--["No sense being pessimistic, it wouldn't work anyway"]-- Opinions==mine

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