diff --git a/drivers/platform/x86/apple-gmux.c b/drivers/platform/x86/apple-gmux.c
index b9429fbf1cd82a403c65bddd09acc6e11078b66a..e743b03f50daa92a3d3898dd6f3f1bd493396049 100644
--- a/drivers/platform/x86/apple-gmux.c
+++ b/drivers/platform/x86/apple-gmux.c
@@ -22,6 +22,7 @@
 #include <linux/delay.h>
 #include <linux/pci.h>
 #include <linux/vga_switcheroo.h>
+#include <linux/vgaarb.h>
 #include <acpi/video.h>
 #include <asm/io.h>
 
@@ -31,6 +32,7 @@ struct apple_gmux_data {
 	bool indexed;
 	struct mutex index_lock;
 
+	struct pci_dev *pdev;
 	struct backlight_device *bdev;
 
 	/* switcheroo data */
@@ -415,6 +417,23 @@ static int gmux_resume(struct device *dev)
 	return 0;
 }
 
+static struct pci_dev *gmux_get_io_pdev(void)
+{
+	struct pci_dev *pdev = NULL;
+
+	while ((pdev = pci_get_class(PCI_CLASS_DISPLAY_VGA << 8, pdev))) {
+		u16 cmd;
+
+		pci_read_config_word(pdev, PCI_COMMAND, &cmd);
+		if (!(cmd & PCI_COMMAND_IO))
+			continue;
+
+		return pdev;
+	}
+
+	return NULL;
+}
+
 static int gmux_probe(struct pnp_dev *pnp, const struct pnp_device_id *id)
 {
 	struct apple_gmux_data *gmux_data;
@@ -425,6 +444,7 @@ static int gmux_probe(struct pnp_dev *pnp, const struct pnp_device_id *id)
 	int ret = -ENXIO;
 	acpi_status status;
 	unsigned long long gpe;
+	struct pci_dev *pdev = NULL;
 
 	if (apple_gmux_data)
 		return -EBUSY;
@@ -475,7 +495,7 @@ static int gmux_probe(struct pnp_dev *pnp, const struct pnp_device_id *id)
 			ver_minor = (version >> 16) & 0xff;
 			ver_release = (version >> 8) & 0xff;
 		} else {
-			pr_info("gmux device not present\n");
+			pr_info("gmux device not present or IO disabled\n");
 			ret = -ENODEV;
 			goto err_release;
 		}
@@ -483,6 +503,23 @@ static int gmux_probe(struct pnp_dev *pnp, const struct pnp_device_id *id)
 	pr_info("Found gmux version %d.%d.%d [%s]\n", ver_major, ver_minor,
 		ver_release, (gmux_data->indexed ? "indexed" : "classic"));
 
+	/*
+	 * Apple systems with gmux are EFI based and normally don't use
+	 * VGA. In addition changing IO+MEM ownership between IGP and dGPU
+	 * disables IO/MEM used for backlight control on some systems.
+	 * Lock IO+MEM to GPU with active IO to prevent switch.
+	 */
+	pdev = gmux_get_io_pdev();
+	if (pdev && vga_tryget(pdev,
+			       VGA_RSRC_NORMAL_IO | VGA_RSRC_NORMAL_MEM)) {
+		pr_err("IO+MEM vgaarb-locking for PCI:%s failed\n",
+			pci_name(pdev));
+		ret = -EBUSY;
+		goto err_release;
+	} else if (pdev)
+		pr_info("locked IO for PCI:%s\n", pci_name(pdev));
+	gmux_data->pdev = pdev;
+
 	memset(&props, 0, sizeof(props));
 	props.type = BACKLIGHT_PLATFORM;
 	props.max_brightness = gmux_read32(gmux_data, GMUX_PORT_MAX_BRIGHTNESS);
@@ -574,6 +611,10 @@ static int gmux_probe(struct pnp_dev *pnp, const struct pnp_device_id *id)
 err_notify:
 	backlight_device_unregister(bdev);
 err_release:
+	if (gmux_data->pdev)
+		vga_put(gmux_data->pdev,
+			VGA_RSRC_NORMAL_IO | VGA_RSRC_NORMAL_MEM);
+	pci_dev_put(pdev);
 	release_region(gmux_data->iostart, gmux_data->iolen);
 err_free:
 	kfree(gmux_data);
@@ -593,6 +634,11 @@ static void gmux_remove(struct pnp_dev *pnp)
 					   &gmux_notify_handler);
 	}
 
+	if (gmux_data->pdev) {
+		vga_put(gmux_data->pdev,
+			VGA_RSRC_NORMAL_IO | VGA_RSRC_NORMAL_MEM);
+		pci_dev_put(gmux_data->pdev);
+	}
 	backlight_device_unregister(gmux_data->bdev);
 
 	release_region(gmux_data->iostart, gmux_data->iolen);