On Thursday 12 May 2005 03:13, Dave Airlie wrote: > Just missed most of this, but we do have drm_device_is_agp(dev) in the > drm, only the CVS radeon uses this at present as the DDX can tell it > also... > > But on Linux it just does.. > pci_find_capability(dev->pdev, PCI_CAP_ID_AGP); > > which sounds like your chip says it is AGP but is connected over a PCI > bus..
The PCI G450s are funky. The chip itself is AGP, but the AGP bus it's on only extends out to the PCI-AGP bridge chip on the card itself. In other words: Host Bridge --[PCI]-- G450 Bridge ==[AGP]== G450 So pci_find_capability isn't right, because it really is an AGP device, there's just no accessible GART. Fortunately the bridge chip is known to be sane (ie, appears topologically between the GPU chip and the host bridge), so he should be able to walk the bus towards the root, find his bridge, and fall back to PCI operation based on that. Or at least that's how I remember the discussion going, right Ian? - ajax
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