Re: [PATCH v2 0/5] PCI: dwc: improve msi handling

Jon Hunter
2020-09-25T08:54:06Z

On 24/09/2020 12:05, Jisheng Zhang wrote:
> Improve the msi code:
> 1. Add proper error handling.
> 2. Move dw_pcie_msi_init() from each users to designware host to solve
> msi page leakage in resume path.

Apologies if this is slightly off topic, but I have been meaning to ask
about MSIs and PCI. On Tegra194 which uses the DWC PCI driver, whenever we
hotplug CPUs we see the following warnings ...

[ 79.068351] WARNING KERN IRQ70: set affinity failed(-22).
[ 79.068362] WARNING KERN IRQ71: set affinity failed(-22).

These interrupts are the MSIs ...

70: 0 0 0 0 0 0 0 0 PCI-MSI 134217728 Edge PCIe PME, aerdrv
71: 0 0 0 0 0 0 0 0 PCI-MSI 134742016 Edge ahci[0001:01:00.0]

This caused because ...

static int dw_pci_msi_set_affinity(struct irq_data *d,
const struct cpumask *mask, bool force)
{
return -EINVAL;
}

Now the above is not unique to the DWC PCI host driver, it appears that
most PCIe drivers also do the same. However, I am curious if there is
any way to avoid the above warnings given that setting the affinity does
not appear to be supported in anyway AFAICT.

Cheers
Jon

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nvpublic