[coreboot] VIA Epia-MII stuff

Markus Törnqvist mjt at nysv.org
Fri Apr 3 12:42:57 CEST 2009

On Thu, Apr 02, 2009 at 06:46:47PM -0400, Corey Osgood wrote:
>2009/4/2 Markus Törnqvist <mjt at nysv.org>

>> http://www.coreboot.org/VIA_EPIA-MII

>> The web says:
>> "The configuration as set up by the buildtarget process will create a
>> coreboot
>> file which is exactly 196608 bytes long, which is exactly 64K bytes short
>> of
>> what needs to go into the 256K flash rom."

>> root at coraline:/usr/src/coreboot-v2-4046/targets/via/epia-m/epia-m# ls -l
>> normal/coreboot.rom fallback/coreboot.rom
>> -rw-r--r-- 1 root src 131072 Apr  2 20:46 fallback/coreboot.rom
>> -rw-r--r-- 1 root src 131072 Apr  2 20:46 normal/coreboot.rom

>> Q1: Why is there a mismatch here?
>Because with the open source xf86-unichrome and Luc Verhaegan's kernel
>driver, it's now possible for the kernel to initialize a framebuffer console
>and X video without the need for the VGA BIOS, so someone decided to change

xf86-unichrome is about drivers for the mobo's integrated vga, right?

>the default to build a 256k image and remove the commented out line with the
>192k size. I believe the console driver is included with recent kernels, but
>I couldn't tell you the exact version. If you want to use a different
>driver, modify this line:
>option ROM_SIZE=256*1024
>to be
>option ROM_SIZE=192*1024

So this should be safest as I'm hoping to use, at least for starters,
a regular Ubuntu kernel, which might not be the latest one but saves
me the trouble of compiling my own?

>Then, re-run buildtarget, make clean, and make. You should end up with a
>128k fallback image and 64k normal image

So I tried ROM_SIZE=192*1024

Payload: 36804 coreboot: 65536 ROM size: 131072 Left space: 28732

Both images are still 128k ...

>(yes, it's a nasty solution, part
>of the reason for v3), and a 192k image in build directory (the one you ran
>make from), that's the image you should probably use. If you want to
>continue using your current solution, you should probably use the fallback
>coreboot.rom, as there is code that will attempt to boot from the fallback
>image in the event of an error, and if there is no fallback image to boot
>from, nasty things could happen. 

... but the build dir coreboot.rom is 256k, not 192k!

I don't know what happened actually, but not surprisingly, it didn't boot,
was just black and nonresponsive.

Maybe I should do the weird-yet-ugly vga-bios-twice hack then, for now.

>If anything's not clear, let me know, I'm
>terrible at explaining things.

Heh, and this should end up on the wiki in some non-confusing format
too so the next guy won't have to ask the same questions :)



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