[coreboot] VGA and Graphics

[ron minnich]

As for graphics startup, here's what I learned when I was doing this in
2012/2013: the kernel could start sandy and ivy with no vbios needed.
However, I have been told that the veil of secrecy has started to draw a
bit closer in subsequent chipsets, and that something like a VGA BIOS/GOP
has to run or graphics will not work. I really don't know, I have not
looked at this in over 3 years.

Todd, just to make sure we're on the same page, VBT is not code, it's a
table -- that's what the T is -- and you can create it any way you want.

Also, as for numbers: the fastest graphics startup, by far, was when we had
coreboot- based startup with configuration specialized to the chromeos
laptop. How fast? At one point we had a pixel booting to chromeos prompt in
2.7 seconds, reduced from 7.7 seconds when linux did the graphics init.
We've seen that the linux graphics init is highly concurrent and
generalized, and that tends to mean slow. Of course this was all far faster
than the 8086-mode vga BIOS supplied by "the vendor". But we were a bit
surprised to see how much faster coreboot was than the linux kernel.

I doubt this speed difference matters any more, since boot time only needs
to be "fast enough" nowadays and 10 seconds seems to do it for most people
-- plus, any 5-second advantage in boot time vanishes as soon as you go to
your first web page.

ron



On Sun, Apr 2, 2017 at 5:31 PM ron minnich <rminnich at gmail.com> wrote:

> So, I'll mention go userland one last time, for a simple reason: I have it
> on good authority that at some places, saying you have a go userland
> instead of a c userland checks a check box on a security checklist. I think
> that's a sensible decision, having watched all the awful ways that C
> programs tend to go wrong :-)
>
> ron
>
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