Attachment 83925 Details for Bug 116364

[patch] kernel boot parameter to disable MSI interrupt usage

msi-disable-willy.patch (text/plain), 4.43 KB, created by Randy Dunlap on 2006-05-17 18:28:29 UTC

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Creator: Randy Dunlap

Created: 2006-05-17 18:28:29 UTC

Size: 4.43 KB

patch

obsolete

>
>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: Matthew Wilcox <matthew@wil.cx>
>Signed-off-by: Randy Dunlap <rdunlap@xenotime.net>
>
>Index: ./Documentation/kernel-parameters.txt
>===================================================================
>RCS file: /var/cvs/linux-2.6/Documentation/kernel-parameters.txt,v
>retrieving revision 1.41.4.1
>diff -u -p -r1.41.4.1 kernel-parameters.txt
>--- ./Documentation/kernel-parameters.txt	18 Feb 2006 05:26:01 -0000	1.41.4.1
>+++ ./Documentation/kernel-parameters.txt	26 Feb 2006 15:58:40 -0000
>@@ -49,6 +49,7 @@ restrictions referred to are that the re
> 	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.
>@@ -1135,6 +1136,9 @@ 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
>Index: ./drivers/pci/Kconfig
>===================================================================
>RCS file: /var/cvs/linux-2.6/drivers/pci/Kconfig,v
>retrieving revision 1.8
>diff -u -p -r1.8 Kconfig
>--- ./drivers/pci/Kconfig	14 Sep 2005 12:56:32 -0000	1.8
>+++ ./drivers/pci/Kconfig	26 Feb 2006 15:58:40 -0000
>@@ -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_LEGACY_PROC
>Index: ./drivers/pci/msi.c
>===================================================================
>RCS file: /var/cvs/linux-2.6/drivers/pci/msi.c,v
>retrieving revision 1.17
>diff -u -p -r1.17 msi.c
>--- ./drivers/pci/msi.c	4 Feb 2006 04:51:55 -0000	1.17
>+++ ./drivers/pci/msi.c	26 Feb 2006 15:58:40 -0000
>@@ -755,6 +755,9 @@ void pci_disable_msi(struct pci_dev* dev
> 	u16 control;
> 	unsigned long flags;
> 
>+	if (!pci_msi_enable)
>+ 		return;
>+
>    	if (!dev || !(pos = pci_find_capability(dev, PCI_CAP_ID_MSI)))
> 		return;
> 
>@@ -1006,6 +1009,9 @@ void pci_disable_msix(struct pci_dev* de
> 	int pos, temp;
> 	u16 control;
> 
>+	if (!pci_msi_enable)
>+ 		return;
>+
>    	if (!dev || !(pos = pci_find_capability(dev, PCI_CAP_ID_MSIX)))
> 		return;
> 
>@@ -1121,6 +1127,11 @@ void msi_remove_pci_irq_vectors(struct p
> 		}
> 		dev->irq = temp;		/* Restore IOAPIC IRQ */
> 	}
>+}
>+
>+void pci_no_msi(void)
>+{
>+	pci_msi_enable = 0;
> }
> 
> EXPORT_SYMBOL(pci_enable_msi);
>Index: ./drivers/pci/pci.c
>===================================================================
>RCS file: /var/cvs/linux-2.6/drivers/pci/pci.c,v
>retrieving revision 1.28
>diff -u -p -r1.28 pci.c
>--- ./drivers/pci/pci.c	4 Feb 2006 04:51:55 -0000	1.28
>+++ ./drivers/pci/pci.c	26 Feb 2006 15:58:40 -0000
>@@ -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;
> 	}
>Index: ./drivers/pci/pci.h
>===================================================================
>RCS file: /var/cvs/linux-2.6/drivers/pci/pci.h,v
>retrieving revision 1.13
>diff -u -p -r1.13 pci.h
>--- ./drivers/pci/pci.h	17 Jan 2006 14:51:41 -0000	1.13
>+++ ./drivers/pci/pci.h	26 Feb 2006 15:58:40 -0000
>@@ -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;
>

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