Re: [PATCH] ARM: dts: tegra: move serial aliases to per-board

[Stephen Warren <swarren@wwwdotorg.org>]

On 11/11/2014 01:49 PM, Olof Johansson wrote:
> There are general changes pending to make the /aliases/serial* entries
> number the serial ports on the system. On tegra, so far the ports have been
> just numbered dynamically as they are configured so that makes them change.
>
> To avoid this, add specific aliases per board to keep the old numbers. This
> allows us to change the numbering by default on future SoCs while keeping the
> numbering on existing boards.

This change seems mostly OK to me. FWIW though, I had suggested this 
approach when the UART aliases were first added, and Laxman disagreed 
with it. See commit b6551bb933f9 "ARM: tegra: dts: add aliases and DMA 
requestor for serial controller", and its discussion: 
https://lkml.org/lkml/2012/12/25/4. I've CC'd Laxman in case he still 
objects.

> Signed-off-by: Olof Johansson <olof@lixom.net>
> ---
>
> Stephen/Thierry/Alex, as noticed this week we really should try to get
> this in before the 3.19 merge window so that the global aliases change
> can happen there without regression.

How did we resolve the issue that patch causes with old DTs; namely that 
it causes a change in behaviour for those old DTs? On IRC, I'd wondered 
whether we should set a flag so the kernel ignored aliases for boards 
containing currently upstreamed Tegra SoCs so that issue wouldn't occur. 
If we did that, we wouldn't need this patch.