Adding some printks reveals it calls r100_init() -> radeon_irq_kms_init() -> drm_irq_install() -> drm_dev_to_irq() and that fails. So no IRQ, no KMS.
lspci does not show Interrupt like on some other PCI devices. /proc/interrupts obviously does not contain the irq since we do not register any yet.
There is no BIOS option of "Enable IRQ for VGA" or similar (BIOS is latest). Could this be the problem?
What can I do to get KMS working on this computer?
-- Meelis Roos (mroos@linux.ee)
Try booting with radeon.agp_mode=-1
radeon: `-1' invalid for parameter `agp_mode'
radeon.agpmode=-1
Still fails in the same place as in the beginning - finding IRQ.
However, I think there are a number of places where we require interrupts that would need to be worked around (fences, display hotplug, pageflipping) if not interrupt is available.
OK.