instead of the deprecated pci_enable_msi* APIs. Signed-off-by: Christoph Hellwig <hch@xxxxxx> --- Documentation/PCI/pci.txt | 24 ++++++++++++------------ 1 file changed, 12 insertions(+), 12 deletions(-) diff --git a/Documentation/PCI/pci.txt b/Documentation/PCI/pci.txt index 77f49dc5be23..98875f8cb7ba 100644 --- a/Documentation/PCI/pci.txt +++ b/Documentation/PCI/pci.txt @@ -382,18 +382,18 @@ The fundamental difference between MSI and MSI-X is how multiple "vectors" get allocated. MSI requires contiguous blocks of vectors while MSI-X can allocate several individual ones. -MSI capability can be enabled by calling pci_enable_msi() or -pci_enable_msix() before calling request_irq(). This causes -the PCI support to program CPU vector data into the PCI device -capability registers. - -If your PCI device supports both, try to enable MSI-X first. -Only one can be enabled at a time. Many architectures, chip-sets, -or BIOSes do NOT support MSI or MSI-X and the call to pci_enable_msi/msix -will fail. This is important to note since many drivers have -two (or more) interrupt handlers: one for MSI/MSI-X and another for IRQs. -They choose which handler to register with request_irq() based on the -return value from pci_enable_msi/msix(). +MSI capability can be enabled by calling pci_alloc_irq_vectors with the +PCI_IRQ_MSI and/or PCI_IRQ_MSIX flags before calling request_irq(). This +causes the PCI support to program CPU vector data into the PCI device +capability registers. Many architectures, chip-sets, or BIOSes do NOT +support MSI or MSI-X and a call to pci_alloc_irq_vectors with just +the PCI_IRQ_MSI and PCI_IRQ_MSIX flags will fail, so try to always +specify PCI_IRQ_LEGACY as well. + +Drivers that have different interrupt handlers for MSI/MSI-X and +legacy INTx should chose the right one based on the msi_enabled +and msix_enabled flags in the pci_dev structure after calling +pci_alloc_irq_vectors. There are (at least) two really good reasons for using MSI: 1) MSI is an exclusive interrupt vector by definition. -- 2.11.0
