Merge branch 'pci/vga'

- Add pci_is_vga() helper, which checks for both PCI_CLASS_DISPLAY_VGA and
  PCI_CLASS_NOT_DEFINED_VGA (which catches ancient devices built before
  Class Codes were defined) (Sui Jingfeng)

- Use the new pci_is_vga() to identify devices for the VGA arbiter, the
  sysfs "boot_vga" attribute, and the virtio and qxl drivers (SUi Jingfeng)

* pci/vga:
  drm/qxl: Use pci_is_vga() to identify VGA devices
  drm/virtio: Use pci_is_vga() to identify VGA devices
  PCI/sysfs: Enable 'boot_vga' attribute via pci_is_vga()
  PCI/VGA: Select VGA devices earlier
  PCI/VGA: Use pci_is_vga() to identify VGA devices
  PCI: Add pci_is_vga() helper

1 files changed, 24 insertions, 0 deletions

diff --git a/include/linux/pci.h b/include/linux/pci.h
index 40ac1288a2cc..ee4b91d2b373 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -713,6 +713,30 @@ static inline bool pci_is_bridge(struct pci_dev *dev)
 		dev->hdr_type == PCI_HEADER_TYPE_CARDBUS;
 }
 
+/**
+ * pci_is_vga - check if the PCI device is a VGA device
+ *
+ * The PCI Code and ID Assignment spec, r1.15, secs 1.4 and 1.1, define
+ * VGA Base Class and Sub-Classes:
+ *
+ *   03 00  PCI_CLASS_DISPLAY_VGA      VGA-compatible or 8514-compatible
+ *   00 01  PCI_CLASS_NOT_DEFINED_VGA  VGA-compatible (before Class Code)
+ *
+ * Return true if the PCI device is a VGA device and uses the legacy VGA
+ * resources ([mem 0xa0000-0xbffff], [io 0x3b0-0x3bb], [io 0x3c0-0x3df] and
+ * aliases).
+ */
+static inline bool pci_is_vga(struct pci_dev *pdev)
+{
+	if ((pdev->class >> 8) == PCI_CLASS_DISPLAY_VGA)
+		return true;
+
+	if ((pdev->class >> 8) == PCI_CLASS_NOT_DEFINED_VGA)
+		return true;
+
+	return false;
+}
+
 #define for_each_pci_bridge(dev, bus)				\
 	list_for_each_entry(dev, &bus->devices, bus_list)	\
 		if (!pci_is_bridge(dev)) {} else