[ add Terry ] Lukas Wunner wrote: > On Wed, Jan 10, 2024 at 01:55:18PM +0100, Bartosz Golaszewski wrote: > > On Tue, Jan 9, 2024 at 3:43???PM Lukas Wunner <lukas@xxxxxxxxx> wrote: > > > On Thu, Jan 04, 2024 at 02:01:17PM +0100, Bartosz Golaszewski wrote: > > > > In order to introduce PCIe power-sequencing, we need to create platform > > > > devices for child nodes of the port driver node. They will get matched > > > > against the pwrseq drivers (if one exists) and then the actuak PCIe > > > > device will reuse the node once it's detected on the bus. > > > [...] > > > > --- a/drivers/pci/pcie/portdrv.c > > > > +++ b/drivers/pci/pcie/portdrv.c > > > > @@ -715,7 +716,7 @@ static int pcie_portdrv_probe(struct pci_dev *dev, > > > > pm_runtime_allow(&dev->dev); > > > > } > > > > > > > > - return 0; > > > > + return devm_of_platform_populate(&dev->dev); > > > > } > > > > > > I think this belongs in of_pci_make_dev_node(), portdrv seems totally > > > the wrong place. Note that you're currently calling this for RCECs > > > (Root Complex Event Collectors) as well, which is likely not what > > > you want. > > > > > > > of_pci_make_dev_node() is only called when the relevant PCI device is > > instantiated which doesn't happen until it's powered-up and scanned - > > precisely the problem I'm trying to address. > > No, of_pci_make_dev_node() is called *before* device_attach(), > i.e. before portdrv has even probed. So it seems this should > work perfectly well for your use case. > > > > > devm functions can't be used in the PCI core, so symmetrically call > > > of_platform_unpopulate() from of_pci_remove_node(). > > > > I don't doubt what you're saying is true (I've seen worse things) but > > this is the probe() callback of a driver using the driver model. Why > > wouldn't devres work? > > The long term plan is to move the functionality in portdrv to > the PCI core. Because devm functions can't be used in the PCI > core, adding new ones to portdrv will *add* a new roadblock to > migrating portdrv to the PCI core. In other words, it makes > future maintenance more difficult. > > Generally, only PCIe port services which share the same interrupt > (hotplug, PME, bandwith notification, flit error counter, ...) > need to live in portdrv. Arbitrary other stuff should not be > shoehorned into portdrv. I came here to say the same thing. It is already the case that portdrv is not a good model to build new functionality upon [1], and PCI core enlightenment should be considered first. The portdrv model is impeding Terry's CXL Port error handling effort, so I am on the lookout for portdrv growing new entanglements to unwind later. [1]: http://lore.kernel.org/r/20221025232535.GA579167@bhelgaas
