[SeaBIOS] Problems booting legacy OSes on Chromebook Pixel 2015 - cbmem output

[edward wandasiewicz]

On Tue, Oct 6, 2015 at 12:53 PM, John Lewis <jlewis at johnlewis.ie> wrote:
>
>
> I'm not absolutely sure how old it is, but I don't think it's any older than
> 2 or 3 weeks, since that was the last time I really had a bash at getting
> this working properly, and I finished up by putting the cbvga option ROM in.
> I guess what this points to is that I should get the script, run by Jenkins,
> to update the cbvga option ROM every time, if I'm going to continue running
> that way.

It was version legacy-230915.

I just updated via https://johnlewis.ie/flash_chromebook_rom.sh and
version is now legacy-021015.

Tried booting the *BSD and Memtest86 with legacy-021015, still get the
same behaviour. No boot.

I've included a cbmem -c for this ROM at

http://pastebin.com/aijH70Zn

>
> If I disable coreboot framebuffer support in SeaBIOS and then use the
> VGABIOS from the stock ROM in RW_LEGACY, I don't get any display from
> SeaBIOS on Broadwell.
>
> If I do the same with a Haswell Chromebook, the display works.
>
> In the former case, SeaBIOS appears to find and load the VGABIOS, according
> to cbmem, just no display.
>
> I think whatever this problem is may also explain why I'm not able to get
> display using a modified BOOT_STUB with SeaBIOS on Broadwell.
>
> Another thing that may or may not have some bearing is that on Baytrail, if
> I try to use RW_LEGACY with SeaBIOS, SeaBIOS initialises the display, but
> Linux won't display anything unless I disable KMS with "nomodeset" on the
> kernel cmdline. That unfortunately leaves me with a display resolution of
> 1024x768 (presumably what coreboot sets the framebuffer to).
>
> If you have some stuff I can try to get a VGABIOS working properly with
> BOOT_STUB and RW_LEGACY on Broadwell and Baytrail Chromebooks, I would sure
> appreciate it, Kevin.
>
> -John.
>
>