[U-Boot-Users] PATCH : Allow dhcp to get IP address from and keep other env data .

Woodruff, Richard r-woodruff2 at ti.com
Wed Jul 30 17:52:24 CEST 2003

Yes that's ok.  I think most of those fields in dhcp are optional, as a
client I think you can even send requests with them included as suggestions
to the server.  A while ago I had some similar issues with the kernel's
built in dhcp code and had read though the RFC back then, but its been a
while (my problem then was ATAGS were not being set properly thus overrides
were not being processed correctly).  The kernel does allow you to dhcp for
an address and allows overrides with what ever the dhcp server sends back
via boot/init parameters.  I would think u-boot should do the same.  

The issue with u-boot would seem to be which and "when" environment variable
parameters should override dhcp server reply  information.  I was taking the
stance that if you have sent them in env then the code should use them even
if they are NOT reasonable.  Effort could be made to check and see if
variables from the environment and reply are reasonable before setting them,
but that seems like to much work at this level....and the desired
functionality can be obtained and now has been sort of documented in


Richard W. 

> -----Original Message-----
> From: Wolfgang Denk [mailto:wd at denx.de] 
> Sent: Wednesday, July 30, 2003 10:35 AM
> To: Woodruff, Richard
> Cc: u-boot-users at lists.sourceforge.net
> Subject: Re: [U-Boot-Users] PATCH : Allow dhcp to get IP 
> address from and keep other env data . 
> In message 
> <FD2AC9A020DDD51194710008C7089B200BEE2232 at dlee17.itg.ti.com> 
> you wrote:
> > 
> > Yes, this does work.  I hadn't considered this sequence. In 
> some sense 
> > it's as much a workaround as a valid solution. The  flexibility of 
> > having a shell like interpreter goes a long way.  I will 
> likely stick 
> > with my code to keeps the steps down.
> I'm not sure what standard behaviour for DHCP requires - for  
> now,  I think I will not change the code. Is this OK with you?
> Best regards,
> Wolfgang Denk
> -- 
> Software Engineering:  Embedded and Realtime Systems,  Embedded Linux
> Phone: (+49)-8142-4596-87  Fax: (+49)-8142-4596-88  Email: 
> wd at denx.de One of the advantages of being a captain is being 
> able to ask for ad- vice without necessarily having to take it.
> 	-- Kirk, "Dagger of the Mind", stardate 2715.2

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