Hi Oliver, Am Donnerstag, 16. März 2023, 15:01:25 CET schrieb Oliver Neukum: > On 16.03.23 14:16, Alexander Stein wrote: > > But isn't the root bridge discovered by the driver (pci-imx6 in this case) > > for that? And the driver probe path eventually calls into the sysfs file > > creation. I compared the file creation to usb, as this is a discoverable > > bus as well. There is no special initialization regarding sysfs. > > If you discover a bus system you always have the option of creating of > virtual hotplug event for the root hub or host controller. > But for PCI that is a bad design choice. USB is different. I'm not sure if I can follow you here. Can you elaborate? > > If, for some reason, the device enumeration for PCI bus during > > imx6_pcie_probe is delayed after pci_sysfs_init initcall, this initcall > > essentially does nothing, no devices or busses to iterate. Which means > > the complete pcie sysfs > On your specific system. You cannot use that as a model for all systems. I am aware that my platform is not a role model for the others. But I've yet to get information what is actually different on other platforms. > > creation is done from bridge probe path. There is no reason to iterate > > over > > discovered PCIe devices/busses separately. > > If there is no other PCI device, the loop is a nop. But otherwise it is > necessary. How is it necessary? How do these PCI devices get attaches to the pci_bus_type bus without calling pci_bus_add_device? > >>> So technically the device is not probed from within a initcall but a > >>> kthread. It is set to be probed asynchronous in imx6_pcie_driver. > >> > >> That may be the problem, respectively that system is incomplete > >> You are registering a PCI bridge. The PCI subsystem should be > >> done setting up when you run. That is just a simple dependency. > > > > Is there such an dependency in the first place? I can't see anything, even > > the late_initcall to pci_resource_alignment_sysfs_init is a different > > matter. > On your hardware, yes. In the kernel, no. > That is the very point. The kernel is missing a way to represent a > dependency. Okay, so which dependency is provided by pci_sysfs_init, which are required by drivers then? Best regards, Alexander -- TQ-Systems GmbH | Mühlstraße 2, Gut Delling | 82229 Seefeld, Germany Amtsgericht München, HRB 105018 Geschäftsführer: Detlef Schneider, Rüdiger Stahl, Stefan Schneider http://www.tq-group.com/
