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    [PATCH] msi: sanely support hardware level msi disabling · f5f2b131
    Eric W. Biederman 提交于
    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: NEric 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: NAndrew Morton <akpm@linux-foundation.org>
    Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
    f5f2b131
msi.c 21.4 KB