I was trying to track some things down and noticed that:
1. legacybios runs the VGA ROM even though Coreboot runs it. I think that legacybios should only run option ROMs if it is not running as a payload. Otherwise the ROM gets run twice.
2. v2 doesn't run the VGA ROM for Qemu, but v3 does. I tried putting in the USES CONFIG_CONSOLE_VGA and defining it to be 1, but it doesn't make a difference. I see in the log where it says it will run the ROM, but I never see the text Plex86/Bochs ... that I see with v3. I know that we don't have to protect our hardware in Qemu, but maybe we should use the emulator so that we use the same pathway for all our v2 targets.
Thanks, Myles
Hi Myles,
On Wed, May 28, 2008 at 03:29:14PM -0600, Myles Watson wrote:
I was trying to track some things down and noticed that:
- legacybios runs the VGA ROM even though Coreboot runs it.
I don't think it is an issue to re-run the vga option rom. I think hitting ctrl+alt+delete effectively re-runs the vga option rom. So, I would think all the vga vendors would make sure re-running was not a problem. Of course, it still increases boot time.
I think that legacybios should only run option ROMs if it is notrunning as a payload. Otherwise the ROM gets run twice.
This isn't so simple. Running the option rom does two things - it inits the card, and it sets up the 16bit vga handlers. Coreboot can init the card, but it isn't designed to fully register the card for 16bit apps.
So, one can easily disable vga option rom execution in legacybios (comment out the first call to rom_scan in post.c), but I don't think it will do what you want it to do.
It should be possible to disable calling the option rom from coreboot, however.
-Kevin
Hi Kevin,
On Wed, May 28, 2008 at 03:29:14PM -0600, Myles Watson wrote:
I was trying to track some things down and noticed that:
- legacybios runs the VGA ROM even though Coreboot runs it.
I don't think it is an issue to re-run the vga option rom. I think hitting ctrl+alt+delete effectively re-runs the vga option rom. So, I would think all the vga vendors would make sure re-running was not a problem. Of course, it still increases boot time.
I think that legacybios should only run option ROMs if it is notrunning as a payload. Otherwise the ROM gets run twice.
This isn't so simple. Running the option rom does two things - it inits the card, and it sets up the 16bit vga handlers. Coreboot can init the card, but it isn't designed to fully register the card for 16bit apps.
What is it missing?
So, one can easily disable vga option rom execution in legacybios (comment out the first call to rom_scan in post.c), but I don't think it will do what you want it to do.
It should be possible to disable calling the option rom from coreboot, however.
That's an interesting problem if you want to have multiple payloads, I guess you're saying that you run the VGA ROM based on which payload you'll eventually select?
Thanks, Myles
-Kevin
-
Kevin O'Connor -
Myles Watson