On Wed, May 04, 2011 at 05:00:31PM +0530, Sagar Borikar wrote:
> I am developing a pci board where I am configuring the ari capability
> in the downstream bridge (device cap 2) and ari cap in the extended
> config space.
> While testing on the rhel 6( 2.6.32 kernel) I see that when I add the
> ari cap, the device doesn't show up in lspci whereas when I don't add
> the ari cap in config space, the device shows up. This is without
> changing the dev cap 2 register in pcie extended capability.
> Just wondering how does linux detect the ari capable device?
Like this (in drivers/pci/probe.c):
int pci_scan_slot(struct pci_bus *bus, int devfn)
{
...
dev = pci_scan_single_device(bus, devfn);
...
if (pci_ari_enabled(bus))
next_fn = next_ari_fn;
else if (dev->multifunction)
next_fn = next_trad_fn;
...
for (fn = next_fn(dev, 0); fn > 0; fn = next_fn(dev, fn)) {
dev = pci_scan_single_device(bus, devfn + fn);
So you should always see function 0 in lspci. If you don't see function
1, then you screwed up your capability somehow :-)
--
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."
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