pci_enable_msix — configure device's MSI-X capability structure
int pci_enable_msix (struct pci_dev * dev, struct msix_entry * entries, int nvec);
devpointer to the pci_dev data structure of MSI-X device function
entriespointer to an array of MSI-X entries
nvecnumber of MSI-X vectors requested for allocation by device driver
Setup the MSI-X capability structure of device function with the number of requested vectors 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 vectors. A return of < 0 indicates a failure. Or a return of > 0 indicates that driver request is exceeding the number of vectors available. Driver should use the returned value to re-send its request.