[U-Boot] [PATCH 3/5] fdt: add fdt_add_display_timings(..)

Stefano Babic sbabic at denx.de
Thu Jan 9 16:06:31 CET 2014


Hi Eric,

On 09/01/2014 15:52, Eric Nelson wrote:
> Hi Stefano,
> 
> On 01/09/2014 03:44 AM, Stefano Babic wrote:
>> Hi Christian,
>>
>> On 09/01/2014 08:12, Christian Gmeiner wrote:
>>
>>>> Agree that we have to sync u-boot and kernel, and this can be a way in
>>>> the short term.
>>>>
>>>> I am asking if this is in the long term the best way to do it. You are
>>>> converting EDID values to fb_videomode *mode, and then again to the
>>>> device node as required by DT.
>>>> We have already had some talks about moving U-Boot configuration to DT,
>>>> that is U-Boot can be also configured by a DT file (see for example
>>>> support for Nvidia processors, they already support DT in U-Boot).
>>>>
>>>
>>> The problem for me here is that DT only does not work in my case. As
>>> it is
>>> possible to attach different panels/displays via lvds (different
>>> timings and resolutions)
>>> we have put an at24 on our print, which contains the suitable EDID data.
>>>
>>> So I need to readout the at24 every boot and need to manipulate the
>>> loaded (emmc) DT.
>>
>> Understood, thanks for clarification. Agree that we need functions for
>> EDID manipulation. My only concern remains if we need a temporary
>> conversion to videomode as in this patch, or we go towards a
>> edid-to-fdt() function.
>>
> 
> I'd really like to keep Christian's patch and use it to remove
> the hard-coded resolutions as shown in SabreSD and Nitrogen6X boards:
> 
>     http://git.denx.de/?p=u-boot.git;a=blob;f=board/freescale/mx6sabresd/mx6sabresd.c;h=9dbe605cf4a5a8ba16c674f14b894ccb59bece9f;hb=HEAD#l266
> 
>     http://git.denx.de/?p=u-boot.git;a=blob;f=board/boundary/nitrogen6x/nitrogen6x.c;h=53cb8dffd0d534629a4de5c7b9798733015adb6e;hb=HEAD#l520
> 

ok - I see also that Christian's patch fills the gap with the display
setup in fdt.

Regards,
Stefano

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