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

Author: bjorn-helgaas

drivers/gpu/drm/qxl/qxl_drv.c

@@ -68,11 +68,6 @@ module_param_named(num_heads, qxl_num_crtc, int, 0400);
 static struct drm_driver qxl_driver;
 static struct pci_driver qxl_pci_driver;
 
-static bool is_vga(struct pci_dev *pdev)
-{
-	return pdev->class == PCI_CLASS_DISPLAY_VGA << 8;
-}
-
 static int
 qxl_pci_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
 {
@@ -100,7 +95,7 @@ qxl_pci_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
 	if (ret)
 		goto disable_pci;
 
-	if (is_vga(pdev) && pdev->revision < 5) {
+	if (pci_is_vga(pdev) && pdev->revision < 5) {
 		ret = vga_get_interruptible(pdev, VGA_RSRC_LEGACY_IO);
 		if (ret) {
 			DRM_ERROR("can't get legacy vga ioports\n");
@@ -131,7 +126,7 @@ qxl_pci_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
 unload:
 	qxl_device_fini(qdev);
 put_vga:
-	if (is_vga(pdev) && pdev->revision < 5)
+	if (pci_is_vga(pdev) && pdev->revision < 5)
 		vga_put(pdev, VGA_RSRC_LEGACY_IO);
 disable_pci:
 	pci_disable_device(pdev);
@@ -159,7 +154,7 @@ qxl_pci_remove(struct pci_dev *pdev)
 
 	drm_dev_unregister(dev);
 	drm_atomic_helper_shutdown(dev);
-	if (is_vga(pdev) && pdev->revision < 5)
+	if (pci_is_vga(pdev) && pdev->revision < 5)
 		vga_put(pdev, VGA_RSRC_LEGACY_IO);
 }
 

drivers/gpu/drm/virtio/virtgpu_drv.c

@@ -51,7 +51,7 @@ static int virtio_gpu_pci_quirk(struct drm_device *dev)
 {
 	struct pci_dev *pdev = to_pci_dev(dev->dev);
 	const char *pname = dev_name(&pdev->dev);
-	bool vga = (pdev->class >> 8) == PCI_CLASS_DISPLAY_VGA;
+	bool vga = pci_is_vga(pdev);
 	int ret;
 
 	DRM_INFO("pci: %s detected at %s\n",

drivers/pci/pci-sysfs.c

@@ -1548,11 +1548,10 @@ static umode_t pci_dev_attrs_are_visible(struct kobject *kobj,
 	struct device *dev = kobj_to_dev(kobj);
 	struct pci_dev *pdev = to_pci_dev(dev);
 
-	if (a == &dev_attr_boot_vga.attr)
-		if ((pdev->class >> 8) != PCI_CLASS_DISPLAY_VGA)
-			return 0;
+	if (a == &dev_attr_boot_vga.attr && pci_is_vga(pdev))
+		return a->mode;
 
-	return a->mode;
+	return 0;
 }
 
 static struct attribute *pci_dev_hp_attrs[] = {

drivers/pci/vgaarb.c

@@ -764,10 +764,6 @@ static bool vga_arbiter_add_pci_device(struct pci_dev *pdev)
 	struct pci_dev *bridge;
 	u16 cmd;
 
-	/* Only deal with VGA class devices */
-	if ((pdev->class >> 8) != PCI_CLASS_DISPLAY_VGA)
-		return false;
-
 	/* Allocate structure */
 	vgadev = kzalloc(sizeof(struct vga_device), GFP_KERNEL);
 	if (vgadev == NULL) {
@@ -1503,6 +1499,10 @@ static int pci_notify(struct notifier_block *nb, unsigned long action,
 
 	vgaarb_dbg(dev, "%s\n", __func__);
 
+	/* Only deal with VGA class devices */
+	if (!pci_is_vga(pdev))
+		return 0;
+
 	/*
 	 * For now, we're only interested in devices added and removed.
 	 * I didn't test this thing here, so someone needs to double check
@@ -1550,8 +1550,10 @@ static int __init vga_arb_device_init(void)
 	pdev = NULL;
 	while ((pdev =
 		pci_get_subsys(PCI_ANY_ID, PCI_ANY_ID, PCI_ANY_ID,
-			       PCI_ANY_ID, pdev)) != NULL)
-		vga_arbiter_add_pci_device(pdev);
+			       PCI_ANY_ID, pdev)) != NULL) {
+		if (pci_is_vga(pdev))
+			vga_arbiter_add_pci_device(pdev);
+	}
 
 	pr_info("loaded\n");
 	return rc;

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