Man page 9 : pci_enable_msix

pci_enable_msix - configure deviceAqs MSI-X capability structure

int pci_enable_msix(struct pci_dev *  dev , struct msix_entry *  entries , int  nvec );

dev
    pointer to the pci_dev data structure of MSI-X device function

entries
    pointer to an array of MSI-X entries

nvec
    number of MSI-X irqs requested for allocation by device driver

Setup the MSI-X capability structure of device function with the number of requested irqs upon its software driver call to request for MSI-X mode enabled on its hardware device function. A return of zero indicates the successful configuration of MSI-X capability structure with new allocated MSI-X irqs. A return of < 0 indicates a failure. Or a return of > 0 indicates that driver request is exceeding the number of irqs or MSI-X vectors available. Driver should use the returned value to re-send its request.