Messages in this thread | | | Date | Mon, 09 Apr 2012 20:43:32 +0900 | From | Kenji Kaneshige <> | Subject | Re: [PATCH 2/2] PCI, ACPI, x86: update MMCFG information when hot-plugging PCI host bridges |
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Your patch looks good to me.
I have some comments.
(2012/04/09 2:12), Jiang Liu wrote: > This patch enhances pci_root driver to update MMCFG information when > hot-plugging PCI root bridges on x86 platforms. >
Do you have the patch that can be applied to Bjorn's pci tree?
<snip.>
> +int arch_acpi_pci_root_add(struct acpi_pci_root *root) > +{ > + int result = 0; > + acpi_status status; > + unsigned long long base_addr; > + struct pci_mmcfg_region *cfg; > + > + /* > + * Try to insert MMCFG information for host bridges with _CBA method > + */ > + status = acpi_evaluate_integer(root->device->handle, METHOD_NAME__CBA, > + NULL,&base_addr); > + if (ACPI_SUCCESS(status)) { > + result = pci_mmconfig_insert(root->segment, > + root->secondary.start, > + root->secondary.end, > + base_addr); > + /* > + * MMCFG information for hot-pluggable host bridges may have > + * already been added by __pci_mmcfg_init(); > + */ > + if (result == -EEXIST) > + result = 0;
Just for confirmation. From my interpretation of PCI firmware spec, MCFG doesn't have any entry for hot-pluggable hostbridge. So I assume this is for the machine that is not compliant to the spec. Is my understanding same as yours?
<snip.>
> static int __devinit acpi_pci_root_add(struct acpi_device *device) > { > unsigned long long segment, bus; > @@ -504,6 +514,14 @@ static int __devinit acpi_pci_root_add(struct acpi_device *device) > strcpy(acpi_device_class(device), ACPI_PCI_ROOT_CLASS); > device->driver_data = root; > > + if (arch_acpi_pci_root_add(root)) { > + printk(KERN_ERR PREFIX > + "can't add MMCFG information for Bus %04x:%02x\n", > + root->segment, (unsigned int)root->secondary.start); > + result = -ENODEV; > + goto out_free; > + }
Desn't this break the system that doesn't support MMCONFIG?
In my understanding, arch_acpi_pci_root_add() returns -ENODEV if mmconfig information is found neither in MCFG table nor _CBA. And pci root bridge initialization seems to fail arch_acpi_pci_root_add() returns non-zero value.
Regards, Kenji Kaneshige
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