---

yaml
---
r: 139373
b: refs/heads/master
c: fafad5b
h: refs/heads/master
i:
  139371: 55147a0
v: v3

[refs]

@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 5546d6f56807115a035d140f7364ce5807dbcc87
+refs/heads/master: fafad5bf06c3a3bb8b24b28b6f065367e7411872

trunk/Documentation/PCI/MSI-HOWTO.txt

@@ -176,7 +176,8 @@ request_irq() for each 'vector' that it decides to use.
 If this function returns a negative number, it indicates an error and
 the driver should not attempt to allocate any more MSI-X interrupts for
 this device.  If it returns a positive number, it indicates the maximum
-number of interrupt vectors that could have been allocated.
+number of interrupt vectors that could have been allocated. See example
+below.
 
 This function, in contrast with pci_enable_msi(), does not adjust
 dev->irq.  The device will not generate interrupts for this interrupt
@@ -187,6 +188,26 @@ free them again later.
 Device drivers should normally call this function once per device
 during the initialization phase.
 
+It is ideal if drivers can cope with a variable number of MSI-X interrupts,
+there are many reasons why the platform may not be able to provide the
+exact number a driver asks for.
+
+A request loop to achieve that might look like:
+
+static int foo_driver_enable_msix(struct foo_adapter *adapter, int nvec)
+{
+	while (nvec >= FOO_DRIVER_MINIMUM_NVEC) {
+		rc = pci_enable_msix(adapter->pdev,
+				     adapter->msix_entries, nvec);
+		if (rc > 0)
+			nvec = rc;
+		else
+			return rc;
+	}
+
+	return -ENOSPC;
+}
+
 4.3.2 pci_disable_msix
 
 void pci_disable_msix(struct pci_dev *dev)