Radeon RV100 init fails with specific card+mobo - IRQ problem

[Alex Deucher]

On Fri, Feb 1, 2013 at 10:26 AM, Meelis Roos <mroos at linux.ee> wrote:
>> > 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 at linux.ee)
>>
>> Try booting with radeon.agp_mode=-1
>
> radeon: `-1' invalid for parameter `agp_mode'

radeon.agpmode=-1

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.

Alex