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Commit 309e57df authored by Matthew Wilcox's avatar Matthew Wilcox Committed by Greg Kroah-Hartman
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[PATCH] PCI: Provide a boot parameter to disable MSI 



Several drivers are starting to grow options to disable MSI.  However,
it's often a host chipset issue, not something which individual drivers
should handle.  So we add the pci=nomsi kernel parameter to allow the user
to disable MSI modes for systems we haven't added to the quirk list yet.

Signed-off-by: default avatarMatthew Wilcox <matthew@wil.cx>
Signed-off-by: default avatarRandy Dunlap <rdunlap@xenotime.net>
Acked-by: default avatarJeff Garzik <jeff@garzik.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
parent 5eeca8e6

Documentation/kernel-parameters.txt

+4 −0
Original line number Diff line number Diff line
@@ -49,6 +49,7 @@ restrictions referred to are that the relevant option is valid if: 
	MCA	MCA bus support is enabled.

	MDA	MDA console support is enabled.

	MOUSE	Appropriate mouse support is enabled.

	MSI	Message Signaled Interrupts (PCI).

	MTD	MTD support is enabled.

	NET	Appropriate network support is enabled.

	NUMA	NUMA support is enabled.
@@ -1152,6 +1153,9 @@ running once the system is up. 
				Mechanism 2.

		nommconf	[IA-32,X86_64] Disable use of MMCONFIG for PCI

				Configuration

		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		[IA-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

drivers/pci/Kconfig

+4 −0
Original line number Diff line number Diff line
@@ -11,6 +11,10 @@ config PCI_MSI 
	   generate an interrupt using an inbound Memory Write on its

	   PCI bus instead of asserting a device IRQ pin.



	   Use of PCI MSI interrupts can be disabled at kernel boot time

	   by using the 'pci=nomsi' option.  This disables MSI for the

	   entire system.



	   If you don't know what to do here, say N.



config PCI_DEBUG

drivers/pci/msi.c

+10 −0
Original line number Diff line number Diff line
@@ -765,8 +765,11 @@ void pci_disable_msi(struct pci_dev* dev) 
	u16 control;

	unsigned long flags;



	if (!pci_msi_enable)

		return;

	if (!dev)

		return;



	pos = pci_find_capability(dev, PCI_CAP_ID_MSI);

	if (!pos)

		return;
@@ -1026,6 +1029,8 @@ void pci_disable_msix(struct pci_dev* dev) 
	int pos, temp;

	u16 control;



	if (!pci_msi_enable)

		return;

	if (!dev)

		return;
@@ -1152,6 +1157,11 @@ void msi_remove_pci_irq_vectors(struct pci_dev* dev) 
	}

}



void pci_no_msi(void)

{

	pci_msi_enable = 0;

}



EXPORT_SYMBOL(pci_enable_msi);

EXPORT_SYMBOL(pci_disable_msi);

EXPORT_SYMBOL(pci_enable_msix);

drivers/pci/pci.c

+6 −2
Original line number Diff line number Diff line
@@ -900,8 +900,12 @@ static int __devinit pci_setup(char *str) 
		if (k)

			*k++ = 0;

		if (*str && (str = pcibios_setup(str)) && *str) {

			/* PCI layer options should be handled here */

			printk(KERN_ERR "PCI: Unknown option `%s'\n", str);

			if (!strcmp(str, "nomsi")) {

				pci_no_msi();

			} else {

				printk(KERN_ERR "PCI: Unknown option `%s'\n",

						str);

			}

		}

		str = k;

	}

drivers/pci/pci.h

+2 −0
Original line number Diff line number Diff line
@@ -50,8 +50,10 @@ extern int pci_msi_quirk; 


#ifdef CONFIG_PCI_MSI

void disable_msi_mode(struct pci_dev *dev, int pos, int type);

void pci_no_msi(void);

#else

static inline void disable_msi_mode(struct pci_dev *dev, int pos, int type) { }

static inline void pci_no_msi(void) { }

#endif



extern int pcie_mch_quirk;