Re: ramstage video display on Chromebook?

Geminilake devices use the FSP PEI GOP driver for display init, so the
display backlight will come on during ramstage (when FSP-S runs), but the
platform does not currently support any output / proof of life prior to the
payload, other than maybe an early boot splash screen (you'd have to look
if GLK supports that).

The truth is though, if your device doesn't boot to the OS, you're going to
need to debug it, and having an indication that it failed in coreboot vs
the payload isn't all that useful when simply connecting the debug cable
and flashing a serial output enabled build will tell you the same thing

On Tue, Dec 19, 2023 at 11:15 AM James Feeney <[email protected]> wrote:

> On 12/18/2023 1:00 PM MST Matt DeVillier <[email protected]> wrote:
> ...
>
> Thanks for all that, Matt.  A little perspective helps me a lot!
>
> I'm wondering, with MrChrombox coreboot will anything normally show on a
> chromebook screen at ramstage, before payload?  Or, if not, can anything be
> *made* to show on the screen, like status or debug info?  I'm thinking, if
> a payload fails, at least something on the screen from coreboot ramstage
> would indicate that coreboot executed up through ramstage, without needing
> to connect a debug cable - and sort of geek eye-candy.
>
> Also, it looks like there is a way to save coreboot debug messages to a
> file.  But, does that use CAR, or would messages be repeatedly written to
> the ROM with every boot?  Maybe cache is too small to use for debug
> messages - geminilake?  Or repeatedly writing to ROM reduces its life?
>

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