[U-Boot] [PATCH v2 1/2] mx6sabresd: Avoid hang when HDMI cable is not connected

[Eric Nelson]

Hi Fabio,

On 09/13/2013 06:58 AM, Fabio Estevam wrote:
> Hi Stefano,
>
> On Fri, Sep 13, 2013 at 5:16 AM, Stefano Babic <sbabic at denx.de> wrote:
>> I admit that using DT also for u-boot seems a better solution. You're
>> right about i.MX6 in kernel, but on the other hand I like how it is
>> described for i.MX28 boards. The display-timings node contain all
>> information we need. It would be nice to have the same for i.MX6.
>
> We currently have the same in DT for mx6 as well. Check this commit,
> for example:
> https://git.kernel.org/cgit/linux/kernel/git/next/linux-next.git/commit/arch/arm/boot/dts/imx6q-sabrelite.dts?id=722cfacd2e719b6447fb4bd5cd3372725876336d
>

Nice!

So, how should we get this done?

We have support for parsing individual lines of DT, and the primary
thing(s) needed by U-Boot's display are in the timing block of the
device tree, but I wonder whether it makes sense to implement a
full parser for that, or a simpler parser for fb_videomode.

Since both cfb_console in U-Boot and the of_get_fb_videomode()
routine in the kernel use fb_videomode, it should be straightforward
to hand the information off.

I don't think the outer information (the lvds-channel at 0 and
ldb blocks in imx6q-sabrelite.dts) should be parsed by U-Boot
as device-tree code since that path leads to having a full
device-tree compiler that seems inappropriate.

Let me know your thoughts.


Eric