I am using Tianocore payload because I require UEFI support. PCI ID for the option ROM is set to 8086:591e (KBL-Y)
config file is attached


From: Matt DeVillier <matt.devillier@gmail.com>
Sent: Monday, February 18, 2019 10:10 PM
To: Alex Feinman
Cc: Nico Huber; coreboot@coreboot.org
Subject: Re: [coreboot] Re: VBIOS/VBT in Coreboot
 
what payload is being used here? If SeaBIOS, you'd ideally want SeaBIOS to run the VGA BIOS, not coreboot (in which case, only the oprom name in cbfs needs to match the PCI ID, not the one in the VBIOS header - only coreboot checks that). You'd set coreboot's display init to none, and simply include the VBIOS and set the PCI ID to match.  That's what I'm doing here for the Purism Librem 13v4/15v4 boards (which are loosely RVP3-based).  Might not hurt to do a 'make savedefconfig' and reply with the contents of defconfig (stripping your board's make/model if needed)


On Mon, Feb 18, 2019 at 11:08 PM Alex Feinman <alexfeinman@hotmail.com> wrote:

Nico, thank you.

I got it to work after enabling the VGA ROM (instead of the GOP driver) and, on advise of a colleague, changing the PCI ID in the VBIOS header from 8086:0406 to the one matching my hardware. Now I see the 0xc0000 segment and intelvbttool can decode VBT. However there is a remaining issue - the video on boot is not present and only comes up when Linux boots. I feel like I need the GOP driver after all.

Best regards
Alex





From: Nico Huber <nico.h@gmx.de>
Sent: Saturday, February 16, 2019 11:05 AM
To: Alex Feinman; coreboot@coreboot.org
Subject: Re: [coreboot] VBIOS/VBT in Coreboot
 
Hello Alex,

On 16.02.19 18:39, Alex Feinman wrote:
> In my Coreboot build I provide both VBIOS and VBT blobs via appropriate
> configuration items. The VBIOS blob contains expected signature at the
> top and VBT is valid as confirmed by running intelvbttool against it.
> The platform is slightly modified kblrvp (RVP3).

AIUI, you only need the VBT. If you are not going to run the VBIOS, you
don't need that one.

>
> During the build I can see cbfstool reporting that both blobs were
> placed in the image: To see the image's read-only sections as well,
> rerun with the -w option.
>
> However, once the system boots, the VBIOS is not found at address
> 0xc0000

You'd have to tell coreboot or a payload to load the VBIOS. AFAIK,
coreboot only does it when you also tell it to use it for gfx init
(`VGA_ROM_RUN`).

> and VBT cannot be located either.  I need VBT to be accessible
> in order to specify the DP connector configuration for eDP. Suggestions
> are appreciated

Maybe check the coreboot console for clues. For instance there should
be a line "ACPI: * IGD OpRegion" telling us that an OpRegion is set up
that points to the VBT.

If that doesn't happen, one possible cause is that your processors SKU
isn't listed here: `src/soc/intel/common/block/graphics/graphics.c:108`.
There is no reliable public source for these IDs. So it's hard to tell
if the list is comprehensive.

In any case, please report back. If you can't find a solution, please
point to the exact code you are using and attach your `.config` file.

Nico
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