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

Jisheng Zhang
2020-09-25T09:19:12Z

Hi Jon,

On Fri, 25 Sep 2020 09:53:45 +0100 Jon Hunter wrote:

>
> 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.
>

Could you please try below patch?

diff --git a/drivers/pci/controller/dwc/pcie-designware-host.c b/drivers/pci/controller/dwc/pcie-designware-host.c
index bf25d783b5c5..7e5dc54d060e 100644
--- a/drivers/pci/controller/dwc/pcie-designware-host.c
+++ b/drivers/pci/controller/dwc/pcie-designware-host.c
@@ -197,7 +197,6 @@ static struct irq_chip dw_pci_msi_bottom_irq_chip = {
.name = "DWPCI-MSI",
.irq_ack = dw_pci_bottom_ack,
.irq_compose_msi_msg = dw_pci_setup_msi_msg,
- .irq_set_affinity = dw_pci_msi_set_affinity,
.irq_mask = dw_pci_bottom_mask,
.irq_unmask = dw_pci_bottom_unmask,
};