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Commit 1ba6ab11 authored by Greg Kroah-Hartman's avatar Greg Kroah-Hartman
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PCI: remove initial bios sort of PCI devices on x86 



We currently keep 2 lists of PCI devices in the system, one in the
driver core, and one all on its own.  This second list is sorted at boot
time, in "BIOS" order, to try to remain compatible with older kernels
(2.2 and earlier days).  There was also a "nosort" option to turn this
sorting off, to remain compatible with even older kernel versions, but
that just ends up being what we have been doing from 2.5 days...

Unfortunately, the second list of devices is not really ever used to 
determine the probing order of PCI devices or drivers[1].  That is done
using the driver core list instead.  This change happened back in the
early 2.5 days.

Relying on BIOS ording for the binding of drivers to specific device
names is problematic for many reasons, and userspace tools like udev
exist to properly name devices in a persistant manner if that is needed,
no reliance on the BIOS is needed.

Matt Domsch and others at Dell noticed this back in 2006, and added a
boot option to sort the PCI device lists (both of them) in a
breadth-first manner to help remain compatible with the 2.4 order, if
needed for any reason.  This option is not going away, as some systems
rely on them.

This patch removes the sorting of the internal PCI device list in "BIOS"
mode, as it's not needed at all anymore, and hasn't for many years.
I've also removed the PCI flags for this from some other arches that for
some reason defined them, but never used them.

This should not change the ordering of any drivers or device probing.

[1] The old-style pci_get_device and pci_find_device() still used this
sorting order, but there are very few drivers that use these functions,
as they are deprecated for use in this manner.  If for some reason, a
driver rely on the order and uses these functions, the breadth-first
boot option will resolve any problem.

Cc: Matt Domsch <Matt_Domsch@dell.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
parent 3b57eff0

Documentation/kernel-parameters.txt

+0 −4
Original line number Diff line number Diff line
@@ -1461,10 +1461,6 @@ and is between 256 and 4096 characters. It is defined in the file 
		nomsi		[MSI] If the PCI_MSI kernel config parameter is

				enabled, this kernel boot option can be used to

				disable the use of MSI interrupts system-wide.

		nosort		[X86-32] Don't sort PCI devices according to

				order given by the PCI BIOS. This sorting is

				done to get a device order compatible with

				older kernels.

		biosirq		[X86-32] Use PCI BIOS calls to get the interrupt

				routing table. These calls are known to be buggy

				on several machines and they hang the machine

arch/frv/mb93090-mb00/pci-frv.h

+0 −2
Original line number Diff line number Diff line
@@ -17,8 +17,6 @@ 
#define PCI_PROBE_BIOS		0x0001

#define PCI_PROBE_CONF1		0x0002

#define PCI_PROBE_CONF2		0x0004

#define PCI_NO_SORT		0x0100

#define PCI_BIOS_SORT		0x0200

#define PCI_NO_CHECKS		0x0400

#define PCI_ASSIGN_ROMS		0x1000

#define PCI_BIOS_IRQ_SCAN	0x2000

arch/mn10300/unit-asb2305/pci-asb2305.h

+0 −2
Original line number Diff line number Diff line
@@ -23,8 +23,6 @@ 
#define PCI_PROBE_BIOS 1

#define PCI_PROBE_CONF1 2

#define PCI_PROBE_CONF2 4

#define PCI_NO_SORT 0x100

#define PCI_BIOS_SORT 0x200

#define PCI_NO_CHECKS 0x400

#define PCI_ASSIGN_ROMS 0x1000

#define PCI_BIOS_IRQ_SCAN 0x2000

arch/sh/drivers/pci/pci-sh4.h

+0 −2
Original line number Diff line number Diff line
@@ -15,8 +15,6 @@ 
#define PCI_PROBE_BIOS		1

#define PCI_PROBE_CONF1		2

#define PCI_PROBE_CONF2		4

#define PCI_NO_SORT		0x100

#define PCI_BIOS_SORT		0x200

#define PCI_NO_CHECKS		0x400

#define PCI_ASSIGN_ROMS		0x1000

#define PCI_BIOS_IRQ_SCAN	0x2000

arch/x86/pci/common.c

+0 −7
Original line number Diff line number Diff line
@@ -427,10 +427,6 @@ static int __init pcibios_init(void) 


	if (pci_bf_sort >= pci_force_bf)

		pci_sort_breadthfirst();

#ifdef CONFIG_PCI_BIOS

	if ((pci_probe & PCI_BIOS_SORT) && !(pci_probe & PCI_NO_SORT))

		pcibios_sort();

#endif

	return 0;

}
@@ -455,9 +451,6 @@ char * __devinit pcibios_setup(char *str) 
	} else if (!strcmp(str, "nobios")) {

		pci_probe &= ~PCI_PROBE_BIOS;

		return NULL;

	} else if (!strcmp(str, "nosort")) {

		pci_probe |= PCI_NO_SORT;

		return NULL;

	} else if (!strcmp(str, "biosirq")) {

		pci_probe |= PCI_BIOS_IRQ_SCAN;

		return NULL;