On Tue, May 25, 2021 at 09:44:26AM +0200, Christoph Hellwig wrote:
> On Thu, May 20, 2021 at 11:33:15AM +0800, Koba Ko wrote:
> > @@ -2958,6 +2959,15 @@ static int nvme_probe(struct pci_dev *pdev, const struct pci_device_id *id)
> >
> > dev_info(dev->ctrl.device, "pci function %s\n", dev_name(&pdev->dev));
> >
> > + if (pm_suspend_via_firmware() || !dev->ctrl.npss ||
> > + !pcie_aspm_enabled(pdev) ||
> > + dev->nr_host_mem_descs ||
> > + (dev->ctrl.quirks & NVME_QUIRK_SIMPLE_SUSPEND)) {
>
> Before we start open coding this in even more places we really want a
> little helper function for these checks, which should be accomodated with
> the comment near the existing copy of the checks.
>
> > + pdev->d3cold_allowed = false;
> > + pci_d3cold_disable(pdev);
> > + pm_runtime_resume(&pdev->dev);
>
> Why do we need to both set d3cold_allowed and call pci_d3cold_disable?
Ugh, this looks pretty hard to maintain.
I don't see why setting d3cold_allowed=false is useful.
pci_d3cold_disable() already sets dev->no_d3cold=true, and the only place
we look at d3cold_allowed is pci_dev_check_d3cold():
if (dev->no_d3cold || !dev->d3cold_allowed || ...)
so we won't even look at d3cold_allowed when no_d3cold is set.
I don't know why we need both no_d3cold and d3cold_allowed in the
first place. 448bd857d48e ("PCI/PM: add PCIe runtime D3cold support")
added them, but without explanation for that.
