Re: [PATCH] Add virtio gpu driver.

On Mi, 2015-03-25 at 18:09 +0100, Michael S. Tsirkin wrote:

On Wed, Mar 25, 2015 at 04:37:16PM +0100, Gerd Hoffmann wrote:

quoted

  Hi,

quoted

BTW can we teach virtio-gpu to look for framebuffer using
virtio pci caps?

The virtio-gpu driver doesn't matter much here, it doesn't use it
anyway.

quoted

 Or are there limitations such as only
using IO port BARs, or compatibility with
BIOS code etc that limit us to specific BARs anyway?

Yes, vgabios code needs to know.  Currently it has bar #2 for the vga
framebuffer bar hardcoded.  It's 16bit code.  I don't feel like making
the probing more complicated ...

cheers,
  Gerd

OK - you are saying all VGA cards use bar #2 for this
functionality, so we are just following
established practice here?

vgabios checks pci ids to figure.  qxl+stdvga use bar #0, vmware-vga bar
#1, virtio-vga bar #2.

cheers,
  Gerd


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