Messages in this thread | | | Date | Tue, 25 May 2021 15:14:42 -0500 | From | Bjorn Helgaas <> | Subject | Re: [PATCH] nvme-pci: Avoid to go into d3cold if device can't use npss. |
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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.
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