[coreboot] Error executing VGA ROM with coreboot

[Mansoor]

> -----Original Message-----
> From: coreboot-bounces+mansoor=iwavesystems.com at coreboot.org
> [mailto:coreboot-bounces+mansoor=iwavesystems.com at coreboot.org] On Behalf
> Of Peter Stuge
> Sent: Sunday, November 01, 2009 4:14 AM
> To: coreboot at coreboot.org
> Subject: Re: [coreboot] Error executing VGA ROM with coreboot
> 
> Mansoor wrote:
> > I have attached the YABEL output.
> 
> Thanks. I think it is helpful. Please follow Kevin's suggestions to
> find out more about what the ROM is trying to do.
> 
> 
 Yes. I will do it

> > Even though coreboot does only the hardware initialization, it has
> > to do a VGA rom init for payloads other than seabios?
> 
> VGA is often not very important for payloads, and option ROMs in
> general fundamentally require a BIOS, which coreboot does not, and
> shall not, offer. If a BIOS environment is needed, then SeaBIOS is
> the way to go.
> 
> 
> > I my case I was planning to use FILO as payload to boot Linux. FILO
> > doesn't do any VGA init.
> 
> In theory it can, if libpayload has native support for your graphics
> hardware. Since this isn't the case, there is no init done. There
> exists only very few graphics drivers in libpayload, which would
> support the idea that graphics is not very important for payloads.
> 
I don't think libpayload has support for my hardware
> 
> I think there are a few options that you can explore further. First,
> maybe the graphics driver in Linux has the ability to initialize
> hardware completely? Because Linux will be started pretty quickly
> with coreboot+FILO, the delay from power on until graphics enabled
> will not be very long even if it is postponed to Linux.
> 
I tried this option. But it didn't initialize VGA

> Second, you can use both SeaBIOS and FILO together. SeaBIOS supports
> booting using another payload file than itself in CBFS. Normally this
> is used as a last resort when there is no local storage or option ROM
> to boot from, but that behavior should be very easy to change in
> SeaBIOS, so that FILO is always used for booting.
> 
> Using multiple payloads will increase boot time, but if legacy VGA
> ROM initialization is a hard requirement then I'm afraid there is no
> substitute for a BIOS environment, such as provided by SeaBIOS.
> 
Thanks for the detailed explanation. 
I am using this method as an alternative (coreboot loads SeaBIOS then
SeaBIOS loads FILO, FILO loads Linux) now. And it works fine. I am using
FILO because I need USB mass storage support. Extra boot time is the seaBIOS
hardware initialization time... and I say it is negligible compared to the
20-30 sec delay of factory BIOS.
  
> But, don't rule out the Linux graphics driver alternative. There
> exists at least one driver (for AMD Geode) which does this, one or
> several of the VIA hardware drivers may also be able to do it. Linux
> 2.6.31 got kernel modesetting support in the Intel framebuffer driver
> so there is a chance. Also, the Intel graphics drivers developers are
> very active in the Linux community, and maybe they can quickly add
> any features that are discovered to be missing at the moment.
> 
> 
> //Peter
> 
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