[coreboot] vga not working

Myles Watson mylesgw at gmail.com
Thu Jul 30 17:56:20 CEST 2009

On Wed, Jul 29, 2009 at 2:31 AM, Arnaud Maye <arnaud.maye at 4dsp.com> wrote:

> * coreboot isn't setting up the pci space with the correct legacy ranges

> We are talking about the GFX cards legacy ranges, right? I think Myles
> looked at the PCI
> allocation already it seems everything is fine there.

Actually I said that it wouldn't be related to the allocator because the
legacy VGA ranges are not aren't allocated there.  This is the place to
start to look for that:

Setting up VGA for PCI: 07:00.0
Setting PCI_BRIDGE_CTL_VGA for bridge PCI: 03:04.0
Setting PCI_BRIDGE_CTL_VGA for bridge PCI: 02:00.0
Setting PCI_BRIDGE_CTL_VGA for bridge PCI: 00:03.0
Setting PCI_BRIDGE_CTL_VGA for bridge PCI_DOMAIN: 0000
Setting PCI_BRIDGE_CTL_VGA for bridge Root Device
Allocating resources...

1. Make sure that that's the path to your graphics card.
2. Make sure that the correct bits get set in each device so that the I/O to
the graphics card gets there.
  - The PCI_BRIDGE_CTL_VGA bit is in the device structure, so it doesn't
affect hardware
  - Many bridges need some bit set to decode those ranges

I guess I don't know how to tell where the I/O gets stopped.  If 2:00.0 is
misconfigured, but 00:03.0 and 3:04.0 are correctly configured, how would
you know?  Most of the ways I can think of to debug that are all or nothing.

I've used PCIe graphics cards with my Tyan boards, and they are initialized
correctly.  I agree with Kevin that a third card will likely have the same
problems you're seeing.

Good luck,
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