Hi, Bjorn,
Gentel ping! Any comments on this patch?
I think this is useful to find whether there is a problem with
the PCI enumeration of the bios or the OS.
在 2021/12/30 下午5:30, Yao Hongbo 写道:
> PCI bridges may be misconfigured by te system BIOS, and then the OS
> scan the bridges that need to be reconfigured.
> However, the PCI bus topology configured by the bios may be wrong:
>
> [ 19.376273] pci 0000:40:00.0: bridge configuration invalid ([bus
> 00-00]), reconfiguring
> [ 19.384443] pci_bus 0000:47: busn_res: can not insert [bus 47-46]
> under [bus 40-46] (conflicts with (null) [bus 40-46])
>
> The primary bus number and subordinate bus number written by the bios
> were wrong, and the OS continues to add bridges on the wrong bus
> topology.
>
> In order to avoid such problems, a kernel cmdline needs to be
> added to support the os to fully configure the pci bus.
>
> Signed-off-by: Yao Hongbo <yaohongbo@xxxxxxxxxxxxxxxxx>
> ---
> Documentation/admin-guide/kernel-parameters.txt | 1 +
> drivers/acpi/pci_root.c | 3 +++
> drivers/pci/pci.c | 5 +++++
> include/linux/pci.h | 2 ++
> 4 files changed, 11 insertions(+)
>
> diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
> index 2fba824..c83a2e5 100644
> --- a/Documentation/admin-guide/kernel-parameters.txt
> +++ b/Documentation/admin-guide/kernel-parameters.txt
> @@ -4084,6 +4084,7 @@
> nomio [S390] Do not use MIO instructions.
> norid [S390] ignore the RID field and force use of
> one PCI domain per PCI function
> + reassign_all_bus The OS fully configure the PCI bus.
>
> pcie_aspm= [PCIE] Forcibly enable or disable PCIe Active State Power
> Management.
> diff --git a/drivers/acpi/pci_root.c b/drivers/acpi/pci_root.c
> index ab2f7df..e21ac25 100644
> --- a/drivers/acpi/pci_root.c
> +++ b/drivers/acpi/pci_root.c
> @@ -592,6 +592,9 @@ static int acpi_pci_root_add(struct acpi_device *device,
> is_pcie = strcmp(acpi_device_hid(device), "PNP0A08") == 0;
> negotiate_os_control(root, &no_aspm, is_pcie);
>
> + if (pci_reassign_all_bus)
> + pci_add_flags(PCI_REASSIGN_ALL_BUS);
> +
> /*
> * TBD: Need PCI interface for enumeration/configuration of roots.
> */
> diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
> index 3d2fb39..5746e88 100644
> --- a/drivers/pci/pci.c
> +++ b/drivers/pci/pci.c
> @@ -142,6 +142,9 @@ bool pci_reset_supported(struct pci_dev *dev)
> /* If set, the PCI config space of each device is printed during boot. */
> bool pci_early_dump;
>
> +/* If set, the pci will reassign resources*/
> +bool pci_reassign_all_bus;
> +
> bool pci_ats_disabled(void)
> {
> return pcie_ats_disabled;
> @@ -6846,6 +6849,8 @@ static int __init pci_setup(char *str)
> pci_add_flags(PCI_SCAN_ALL_PCIE_DEVS);
> } else if (!strncmp(str, "disable_acs_redir=", 18)) {
> disable_acs_redir_param = str + 18;
> + } else if (!strncmp(str, "reassign_all_bus", 16)) {
> + pci_reassign_all_bus = true;
> } else {
> pr_err("PCI: Unknown option `%s'\n", str);
> }
> diff --git a/include/linux/pci.h b/include/linux/pci.h
> index 18a75c8e..ad0e3e9 100644
> --- a/include/linux/pci.h
> +++ b/include/linux/pci.h
> @@ -2119,6 +2119,8 @@ int pcim_iomap_regions_request_all(struct pci_dev *pdev, int mask,
> extern u8 pci_dfl_cache_line_size;
> extern u8 pci_cache_line_size;
>
> +extern bool pci_reassign_all_bus;
> +
> /* Architecture-specific versions may override these (weak) */
> void pcibios_disable_device(struct pci_dev *dev);
> void pcibios_set_master(struct pci_dev *dev);
