Hi,

On Sun, Feb 10, 2019 at 2:18 PM Nico Huber <[email protected]> wrote:
>
> The usual workaround is to add a predicate that is selected by the
> board. e.g.
>
>     config FRAMEBUFFER_VESA_DEFAULT_118
>             bool
>
>     choice
>             default FRAMEBUFFER_VESA_MODE_118 if
> FRAMEBUFFER_VESA_DEFAULT_118
>
> Not pretty either, but generally accepted. src/mainboard/Kconfig starts
> with an example of this pattern.
>

Thank you very much for your advice and inspiration! I just made a new
change https://review.coreboot.org/c/coreboot/+/31324 , and you are
welcome for review.

> I don't understand the current 117 default. I remember it was a
> common mode in the legacy BIOS days. But for legacy boot, you
> wouldn't want to run the VGA BIOS in coreboot. It might be worth
> to test (with all currently integrated payloads) if 118 isn't a
> better default. Assuming 118 means 4-byte pixels? I would expect
> it to be more compatible.

The main difference between 117h and 118h modes is the number of
colors: 117h = 16-bit (2 byte) pixel - 64k colors, 118h = 24-bit
(3-byte) pixel - 16M colors.

To be honest I don't know how the number of colors affect the
compatibility, especially for the older coreboot boards, so I think
the safer approach would be to leave the default as 117h while maybe
choosing the other better defaults for the boards where they have been
tested.

We already tested 118h mode at G505S and it's working well there,
although with VGABIOS added (no native graphics init yet) :

> On Sat, Nov 3, 2018 at 8:42 PM Hans Jürgen Kitter wrote:
> Coreboot config: std. g505s build, but both run oprom & load oprom was 
> enabled (native mode), also display was set to FB, 1024x768 16.8M color 
> 8:8:8, legacy VGA → this provides console output even if eg. GRUB is the 
> payload).

( the message above is related to HJK patches for making a dGPU
working at G505S, currently I'm looking through these patches and hope
to upstream them in the near future)

So I'm suggesting these Kconfig options for G505S (
FRAMEBUFFER_SET_VESA_MODE and FRAMEBUFFER_VESA_DEFAULT_118 ) at
another new https://review.coreboot.org/c/coreboot/+/31325 change

Best regards,
Mike Banon
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