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SubjectRe: [PATCH v2] of: Support CONFIG_CMDLINE_EXTEND config option

On Thu, Jul 10, 2014 at 12:33 AM, John Stultz <> wrote:
> On Fri, Jan 13, 2012 at 11:15 PM, Doug Anderson <> wrote:
>> The old logic assumes CMDLINE_FROM_BOOTLOADER vs. CMDLINE_FORCE and
>> ignores CMDLINE_EXTEND. Here's the old logic:
>> - dt bootargs=non-empty:
>> dt bootargs
>> - dt bootargs=empty, @data is non-empty string
>> @data is left unchanged
>> - dt bootargs=empty, @data is empty string
>> CONFIG_CMDLINE (or "" if that's not defined)
>> The new logic is now documented in of_fdt.h and is copied here for
>> reference:
>> - CONFIG_CMDLINE_EXTEND=true, @data is non-empty string
>> @data + dt bootargs (even if dt bootargs are empty)
>> - CONFIG_CMDLINE_EXTEND=true, @data is empty string
>> CONFIG_CMDLINE + dt bootargs (even if dt bootargs are empty)
>> - CMDLINE_FROM_BOOTLOADER=true, dt bootargs=non-empty:
>> dt bootargs
>> - CMDLINE_FROM_BOOTLOADER=true, dt bootargs=empty, @data is non-empty string
>> @data is left unchanged
>> - CMDLINE_FROM_BOOTLOADER=true, dt bootargs=empty, @data is empty string
>> CONFIG_CMDLINE (or "" if that's not defined)
>> Signed-off-by: Doug Anderson <>
>> CC:
>> CC: Grant Likely <>
>> CC: Benjamin Herrenschmidt <>
>> CC: Rob Herring <>
>> ---
>> I didn't hear a response from Ben about whether he was OK with
>> my proposal for how CONFIG_CMDLINE_EXTEND should behave with
>> a non-empty @data, so sending out code that implements my
>> interpretation. Hopefully this looks OK.
>> Changes in v2:
>> - Removed broken fix for the case when there is no "chosen" attribute.
>> - Changed CONFIG_CMDLINE_EXTEND behavior when @data is a non-empty string.
> In reviewing some of the random patches in the Android AOSP common.git
> tree, I noticed this one, and found this discussion which petered out
> without resolution. Were there any objections still, or did this just
> slip through the cracks?

I gave up and decided not to keep pushing and solved the problem
another way myself. ...but I still agree that it's a reasonable thing
to do. I haven't really thought about this in several years now...

I do remember seeing
where Colin looked to be making a bunch of changes to the patch before
merging, but I guess he ended up splitting that into a cleanup patch.
I think I pinged him to ask if he wanted me to get involved in the
review but I got no response.

> Note, there's also this follow-on fix from Colin, which probably
> should be included if the parent patch is merged:

OK. Seems reasonable to me. I haven't done a full review of all of
the boundary conditions here, but otherwise it looks fine.

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