vga_switcheroo: split switching into two stages.

stage 1: turn card on, switch boot vga pointer.
stage 2: switch fbs, switch mux and power off old card.
Signed-off-by: Dave Airlie <airlied@redhat.com>

drivers/gpu/vga/vga_switcheroo.c

@@ -212,7 +212,8 @@ static int vga_switchoff(struct vga_switcheroo_client *client)
 	return 0;
 }
 
-static int vga_switchto(struct vga_switcheroo_client *new_client)
+/* stage one happens before delay */
+static int vga_switchto_stage1(struct vga_switcheroo_client *new_client)
 {
 	int ret;
 	int i;
@@ -239,10 +240,28 @@ static int vga_switchto(struct vga_switcheroo_client *new_client)
 		vga_switchon(new_client);
 
 	/* swap shadow resource to denote boot VGA device has changed so X starts on new device */
-	active->active = false;
-
 	active->pdev->resource[PCI_ROM_RESOURCE].flags &= ~IORESOURCE_ROM_SHADOW;
 	new_client->pdev->resource[PCI_ROM_RESOURCE].flags |= IORESOURCE_ROM_SHADOW;
+	return 0;
+}
+
+/* post delay */
+static int vga_switchto_stage2(struct vga_switcheroo_client *new_client)
+{
+	int ret;
+	int i;
+	struct vga_switcheroo_client *active = NULL;
+
+	for (i = 0; i < VGA_SWITCHEROO_MAX_CLIENTS; i++) {
+		if (vgasr_priv.clients[i].active == true) {
+			active = &vgasr_priv.clients[i];
+			break;
+		}
+	}
+	if (!active)
+		return 0;
+
+	active->active = false;
 
 	if (new_client->fb_info) {
 		struct fb_event event;
@@ -368,18 +387,22 @@ vga_switcheroo_debugfs_write(struct file *filp, const char __user *ubuf,
 
 	if (can_switch == true) {
 		pdev_name = pci_name(client->pdev);
-		ret = vga_switchto(client);
+		ret = vga_switchto_stage1(client);
+		if (ret)
+			printk(KERN_ERR "vga_switcheroo: switching failed stage 1 %d\n", ret);
+
+		ret = vga_switchto_stage2(client);
 		if (ret)
-			printk(KERN_ERR "vga_switcheroo: switching failed %d\n", ret);
+			printk(KERN_ERR "vga_switcheroo: switching failed stage 2 %d\n", ret);
+
 	} else {
 		printk(KERN_INFO "vga_switcheroo: setting delayed switch to client %d\n", client->id);
 		vgasr_priv.delayed_switch_active = true;
 		vgasr_priv.delayed_client_id = client_id;
 
-		/* we should at least power up the card to
-		   make the switch faster */
-		if (client->pwr_state == VGA_SWITCHEROO_OFF)
-			vga_switchon(client);
+		ret = vga_switchto_stage1(client);
+		if (ret)
+			printk(KERN_ERR "vga_switcheroo: delayed switching stage 1 failed %d\n", ret);
 	}
 
 out:
@@ -461,9 +484,9 @@ int vga_switcheroo_process_delayed_switch(void)
 		goto err;
 
 	pdev_name = pci_name(client->pdev);
-	ret = vga_switchto(client);
+	ret = vga_switchto_stage2(client);
 	if (ret)
-		printk(KERN_ERR "vga_switcheroo: delayed switching failed %d\n", ret);
+		printk(KERN_ERR "vga_switcheroo: delayed switching failed stage 2 %d\n", ret);
 
 	vgasr_priv.delayed_switch_active = false;
 	err = 0;