broken msi interrupts with radeon rv570 on amd 8151 agp bridge

[Matthew Wilcox]

On Thu, Nov 05, 2009 at 01:57:10PM +0100, Daniel Vetter wrote:
> When starting a failsafe X session and starting glxgears (which should
> cause plenty of interrupts to be generated), /proc/interrupts shows
> absolutely no MSI interrupts arriving. There are no other devices in this
> box using MSI interrupts.
> 
> I've also tried with the lastest -linus git tree merged in, with the same
> effects.
> 
> Booting with "pci=nomsi" works around the issue. I dunno whether this is a
> pci or radeon issue therefore I'm posting to both lists. lspci -v (as
> root) is attached below.

That sucks, and we need to fix it.

It's almost certainly a chipset issue, so my suspicion falls primarily
on this device:
04:01.0 PCI bridge: Advanced Micro Devices [AMD] AMD-8151 AGP Bridge (rev 14) (prog-if 00 [Normal decode])

We have a number of quirks to handle MSIs (both disabling their use, and
programming the feature in bridges that the BIOS forgot to set up) on
HyperTransport machines already; could you send both lspci -t and
lspci -vvvnn (as root) to the linux-pci list?

I don't believe this is a Radeon issue, so I think you can drop the cc
to that list.

-- 
Matthew Wilcox				Intel Open Source Technology Centre
"Bill, look, we understand that you're interested in selling us this
operating system, but compare it to ours.  We can't possibly take such
a retrograde step."