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From: Mitch Bradley <wmb-D5eQfiDGL7eakBO8gow8eQ@public.gmane.org>
To: Grant Likely <grant.likely-s3s/WqlpOiPyB63q8FvJNQ@public.gmane.org>
Cc: devicetree-discuss
	<devicetree-discuss-uLR06cmDAlY/bJ5BZ2RsiQ@public.gmane.org>,
	arm-TuqUDEhatI4ANWPb/1PvSmm0pvjS0E/A@public.gmane.org
Subject: Re: precedence of built-in vs. platform trees?
Date: Thu, 29 Nov 2012 06:06:40 -1000	[thread overview]
Message-ID: <50B78810.8010508@firmworks.com> (raw)
In-Reply-To: <CACxGe6uc-E2kHuQeKbJNDgEWLa_DLqDRzC4eRyKReeZTVdQVeA-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>

On 11/29/2012 1:46 AM, Grant Likely wrote:
> On Thu, Nov 29, 2012 at 6:39 AM, Jon Masters <jonathan-Zp4isUonpHBD60Wz+7aTrA@public.gmane.org> wrote:
>> Hey guys,
>>
>> I apologize if I should have RTFM. If a platform provides a device tree
>> at boot time, and the kernel also has a tree appended, what behavior is
>> supposed to happen? i.e. what is the standard that is anticipated here?
> 
> Hmmm, nobody has asked that before. I don't think it is really defined :-)
> 
> I presume that the built-in DT will end up getting used from what I
> remember about the code.

That sounds like the right default, but it would be nice if one could
override it with a cmdline option.  It's *usually* easier to change the
kernel than the platform firmware or bootloader, but there are
exceptions.  In our (OLPC's) case, DT mods can be made trivially by
editing a script (and the firmware includes an editor).  We use this
feature all the time in development, and sometimes even for customers,
for testing bug fixes.

> 
> g.
> _______________________________________________
> devicetree-discuss mailing list
> devicetree-discuss-uLR06cmDAlY/bJ5BZ2RsiQ@public.gmane.org
> https://lists.ozlabs.org/listinfo/devicetree-discuss
> 

      parent reply	other threads:[~2012-11-29 16:06 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-11-29  6:39 [fedora-arm] precedence of built-in vs. platform trees? Jon Masters
     [not found] ` <50B7033C.3030204-Zp4isUonpHBD60Wz+7aTrA@public.gmane.org>
2012-11-29 11:06   ` Leif Lindholm
2012-11-29 11:46   ` Grant Likely
     [not found]     ` <CACxGe6uc-E2kHuQeKbJNDgEWLa_DLqDRzC4eRyKReeZTVdQVeA-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2012-11-29 16:06       ` Mitch Bradley [this message]

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