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PCI: Allow additional bus numbers for hotplug bridges

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A user may hot add a switch requiring more than one bus to enumerate.  This
previously required a system reboot if BIOS did not sufficiently pad the
bus resource, which they frequently don't do.

Add a kernel parameter so a user can specify the minimum number of bus
numbers to reserve for a hotplug bridge's subordinate buses so rebooting
won't be necessary.

The default is 1, which is equivalent to previous behavior.

Signed-off-by: Keith Busch <keith.busch@intel.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
This commit is contained in:
Keith Busch
2016-07-21 21:40:28 -06:00
committed by Bjorn Helgaas
parent af8c34ce6a
commit e16b466059
4 changed files with 21 additions and 0 deletions
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8
drivers/pci/pci.c
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@@ -81,6 +81,9 @@ unsigned long pci_cardbus_mem_size = DEFAULT_CARDBUS_MEM_SIZE;
unsigned long pci_hotplug_io_size = DEFAULT_HOTPLUG_IO_SIZE;
unsigned long pci_hotplug_mem_size = DEFAULT_HOTPLUG_MEM_SIZE;
#define DEFAULT_HOTPLUG_BUS_SIZE 1
unsigned long pci_hotplug_bus_size = DEFAULT_HOTPLUG_BUS_SIZE;
enum pcie_bus_config_types pcie_bus_config = PCIE_BUS_DEFAULT;
/*
@@ -5021,6 +5024,11 @@ static int __init pci_setup(char *str)
pci_hotplug_io_size = memparse(str + 9, &str);
} else if (!strncmp(str, "hpmemsize=", 10)) {
pci_hotplug_mem_size = memparse(str + 10, &str);
} else if (!strncmp(str, "hpbussize=", 10)) {
pci_hotplug_bus_size =
simple_strtoul(str + 10, &str, 0);
if (pci_hotplug_bus_size > 0xff)
pci_hotplug_bus_size = DEFAULT_HOTPLUG_BUS_SIZE;
} else if (!strncmp(str, "pcie_bus_tune_off", 17)) {
pcie_bus_config = PCIE_BUS_TUNE_OFF;
} else if (!strncmp(str, "pcie_bus_safe", 13)) {