[PATCH V6 04/12] PCI/VGA: Prefer VGA device with legacy I/O enabled

[Huacai Chen]

This patch is the second step of the rework: A VGA device with legacy
I/O resources enabled is more preferred than those not enabled.

Signed-off-by: Huacai Chen <chenhuacai at loongson.cn>
Signed-off-by: Bjorn Helgaas <bhelgaas at google.com>
---
 drivers/gpu/vga/vgaarb.c | 19 ++++++++++++++++---
 1 file changed, 16 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/vga/vgaarb.c b/drivers/gpu/vga/vgaarb.c
index f8f95244d499..1ffc3decc9cb 100644
--- a/drivers/gpu/vga/vgaarb.c
+++ b/drivers/gpu/vga/vgaarb.c
@@ -582,14 +582,27 @@ static bool vga_arb_integrated_gpu(struct device *dev)
 static void vga_arb_update_default_device(struct vga_device *vgadev)
 {
 	struct pci_dev *pdev = vgadev->pdev;
+	struct device *dev = &pdev->dev;
+	struct vga_device *vgadev_default;
 
 	/*
 	 * If we don't have a default VGA device yet, and this device owns
 	 * the legacy VGA resources, make it the default.
 	 */
-	if (!vga_default_device() &&
-	    ((vgadev->owns & VGA_RSRC_LEGACY_MASK) == VGA_RSRC_LEGACY_MASK)) {
-		vgaarb_info(&pdev->dev, "setting as boot VGA device\n");
+	if (!vga_default_device()) {
+		if ((vgadev->owns & VGA_RSRC_LEGACY_MASK) == VGA_RSRC_LEGACY_MASK)
+			vgaarb_info(dev, "setting as boot VGA device\n");
+		else
+			vgaarb_info(dev, "setting as boot device (VGA legacy resources not available)\n");
+		vga_set_default_device(pdev);
+	}
+
+	vgadev_default = vgadev_find(vga_default);
+
+	/* Overridden by a better device */
+	if (vgadev_default && ((vgadev_default->owns & VGA_RSRC_LEGACY_MASK) == 0)
+		&& ((vgadev->owns & VGA_RSRC_LEGACY_MASK) == VGA_RSRC_LEGACY_MASK)) {
+		vgaarb_info(dev, "overriding boot VGA device\n");
 		vga_set_default_device(pdev);
 	}
 }
-- 
2.27.0