[PATCH] msi: sanely support hardware level msi disabling

In some cases when we are not using msi we need a way to ensure that the
hardware does not have an msi capability enabled.  Currently the code has been
calling disable_msi_mode to try and achieve that.  However disable_msi_mode
has several other side effects and is only available when msi support is
compiled in so it isn't really appropriate.

Instead this patch implements pci_msi_off which disables all msi and msix
capabilities unconditionally with no additional side effects.

pci_disable_device was redundantly clearing the bus master enable flag and
clearing the msi enable bit.  A device that is not allowed to perform bus
mastering operations cannot generate intx or msi interrupt messages as those
are essentially a special case of dma, and require bus mastering.  So the call
in pci_disable_device to disable msi capabilities was redundant.

quirk_pcie_pxh also called disable_msi_mode and is updated to use pci_msi_off.

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Cc: Michael Ellerman <michael@ellerman.id.au>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Greg KH <greg@kroah.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 0 insertions, 2 deletions

diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h
index a4f2d580625..ae7a975995a 100644
--- a/drivers/pci/pci.h
+++ b/drivers/pci/pci.h
@@ -46,10 +46,8 @@ extern struct rw_semaphore pci_bus_sem;
 extern unsigned int pci_pm_d3_delay;
 
 #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