On Thu, Oct 4, 2012 at 3:36 PM, Rafael J. Wysocki <rjw@xxxxxxx> wrote: > On Thursday 04 of October 2012 15:01:21 Yinghai Lu wrote: >> during adding pci root bus hotplug, Bjorn found some unsafe searching >> that caused by pci_bus_add_devices. > > Do you have a link to a description of that problem? Maybe bjorn could expand it more. > >> pci devices are created during pci scan root, but until very late >> acpi_pci_root_start call pci_bus_add_devices. > > So you mean that pci_bus_add_devices() is called too late, right? yes. > >> To fill the gap, we need to move pci_bus_add_devices to acpi_pci_root_add >> at first. >> >> but after we move that there, pci device will be added to device tree, and it >> will try to bind with acpi devices that should be under acpi pci root, >> but are not >> created yet. because device_add for acpi_device for acpi pci root is done yet. >> it still calling the .add in the acpi_driver aka acpi_pci_root_add. > > Quite obviously, we haven't walked the ACPI namespace below the host bridge > object yet at that point. yes. > >> So I want to hold the driver attach for pci root acpi devices, and >> later attach it >> until pci devices created. >> >> booting path, all acpi devices get created, and attach driver for them >> one by one. > > I see. > > Your patches seem to affect all devices in the ACPI namespace added after > boot, though, not only host bridges. yes, but it still should be safe. > > And the problem seems to be that the scanning of the ACPI namespace and > configuring the host bridge are kind of independent operations now. What > we should do, actually, seems to be something like this: > > (1) Configure the host bridge when discovered (i.e. do what the current > acpi_pci_root_add() does. > (2) Parse the ACPI namespace under the host bridge (without binding ACPI > drivers to the struct acpi_device objects created in the process, > because they are known to correspond to PCI devices). > (3) Run pci_bus_add_devices() for the bridge. > > in one routine. problem is still there. if 1 still has acpi_pci_root_add and pci_acpi_scan_root that scan pci devices. what is need is we need to bind 1 and 3 together. or we could move pci_scan_root_scan from acpi_pci_root_add to acpi_pci_root_start? -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
