1 files changed, 201 insertions, 80 deletions

diff --git a/drivers/gpu/vga/vgaarb.c b/drivers/gpu/vga/vgaarb.c
index 1ac0c93603c..af025970835 100644
--- a/drivers/gpu/vga/vgaarb.c
+++ b/drivers/gpu/vga/vgaarb.c
@@ -1,12 +1,32 @@
 /*
- * vgaarb.c
+ * vgaarb.c: Implements the VGA arbitration. For details refer to
+ * Documentation/vgaarbiter.txt
+ *
  *
  * (C) Copyright 2005 Benjamin Herrenschmidt <benh@kernel.crashing.org>
  * (C) Copyright 2007 Paulo R. Zanoni <przanoni@gmail.com>
  * (C) Copyright 2007, 2009 Tiago Vignatti <vignatti@freedesktop.org>
  *
- * Implements the VGA arbitration. For details refer to
- * Documentation/vgaarbiter.txt
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+ * DEALINGS
+ * IN THE SOFTWARE.
+ *
  */
 
 #include <linux/module.h>
@@ -20,6 +40,7 @@
 #include <linux/spinlock.h>
 #include <linux/poll.h>
 #include <linux/miscdevice.h>
+#include <linux/slab.h>
 
 #include <linux/uaccess.h>
 
@@ -40,7 +61,7 @@ struct vga_device {
 	unsigned int mem_lock_cnt;	/* legacy MEM lock count */
 	unsigned int io_norm_cnt;	/* normal IO count */
 	unsigned int mem_norm_cnt;	/* normal MEM count */
-
+	bool bridge_has_one_vga;
 	/* allow IRQ enable/disable hook */
 	void *cookie;
 	void (*irq_set_state)(void *cookie, bool enable);
@@ -115,6 +136,17 @@ struct pci_dev *vga_default_device(void)
 {
 	return vga_default;
 }
+
+EXPORT_SYMBOL_GPL(vga_default_device);
+
+void vga_set_default_device(struct pci_dev *pdev)
+{
+	if (vga_default == pdev)
+		return;
+
+	pci_dev_put(vga_default);
+	vga_default = pci_dev_get(pdev);
+}
 #endif
 
 static inline void vga_irq_set_state(struct vga_device *vgadev, bool state)
@@ -130,7 +162,7 @@ static inline void vga_irq_set_state(struct vga_device *vgadev, bool state)
 static void vga_check_first_use(void)
 {
 	/* we should inform all GPUs in the system that
-	 * VGA arb has occured and to try and disable resources
+	 * VGA arb has occurred and to try and disable resources
 	 * if they can */
 	if (!vga_arbiter_used) {
 		vga_arbiter_used = true;
@@ -144,6 +176,8 @@ static struct vga_device *__vga_tryget(struct vga_device *vgadev,
 	unsigned int wants, legacy_wants, match;
 	struct vga_device *conflict;
 	unsigned int pci_bits;
+	u32 flags = 0;
+
 	/* Account for "normal" resources to lock. If we decode the legacy,
 	 * counterpart, we need to request it as well
 	 */
@@ -154,8 +188,8 @@ static struct vga_device *__vga_tryget(struct vga_device *vgadev,
 	    (vgadev->decodes & VGA_RSRC_LEGACY_MEM))
 		rsrc |= VGA_RSRC_LEGACY_MEM;
 
-	pr_devel("%s: %d\n", __func__, rsrc);
-	pr_devel("%s: owns: %d\n", __func__, vgadev->owns);
+	pr_debug("%s: %d\n", __func__, rsrc);
+	pr_debug("%s: owns: %d\n", __func__, vgadev->owns);
 
 	/* Check what resources we need to acquire */
 	wants = rsrc & ~vgadev->owns;
@@ -216,21 +250,28 @@ static struct vga_device *__vga_tryget(struct vga_device *vgadev,
 		/* looks like he doesn't have a lock, we can steal
 		 * them from him
 		 */
-		vga_irq_set_state(conflict, false);
 
+		flags = 0;
 		pci_bits = 0;
-		if (lwants & (VGA_RSRC_LEGACY_MEM|VGA_RSRC_NORMAL_MEM))
-			pci_bits |= PCI_COMMAND_MEMORY;
-		if (lwants & (VGA_RSRC_LEGACY_IO|VGA_RSRC_NORMAL_IO))
-			pci_bits |= PCI_COMMAND_IO;
 
-		pci_set_vga_state(conflict->pdev, false, pci_bits,
-				  change_bridge);
-		conflict->owns &= ~lwants;
+		if (!conflict->bridge_has_one_vga) {
+			vga_irq_set_state(conflict, false);
+			flags |= PCI_VGA_STATE_CHANGE_DECODES;
+			if (match & (VGA_RSRC_LEGACY_MEM|VGA_RSRC_NORMAL_MEM))
+				pci_bits |= PCI_COMMAND_MEMORY;
+			if (match & (VGA_RSRC_LEGACY_IO|VGA_RSRC_NORMAL_IO))
+				pci_bits |= PCI_COMMAND_IO;
+		}
+
+		if (change_bridge)
+			flags |= PCI_VGA_STATE_CHANGE_BRIDGE;
+
+		pci_set_vga_state(conflict->pdev, false, pci_bits, flags);
+		conflict->owns &= ~match;
 		/* If he also owned non-legacy, that is no longer the case */
-		if (lwants & VGA_RSRC_LEGACY_MEM)
+		if (match & VGA_RSRC_LEGACY_MEM)
 			conflict->owns &= ~VGA_RSRC_NORMAL_MEM;
-		if (lwants & VGA_RSRC_LEGACY_IO)
+		if (match & VGA_RSRC_LEGACY_IO)
 			conflict->owns &= ~VGA_RSRC_NORMAL_IO;
 	}
 
@@ -240,14 +281,24 @@ enable_them:
 	 * also have in "decodes". We can lock resources we don't decode but
 	 * not own them.
 	 */
+	flags = 0;
 	pci_bits = 0;
-	if (wants & (VGA_RSRC_LEGACY_MEM|VGA_RSRC_NORMAL_MEM))
-		pci_bits |= PCI_COMMAND_MEMORY;
-	if (wants & (VGA_RSRC_LEGACY_IO|VGA_RSRC_NORMAL_IO))
-		pci_bits |= PCI_COMMAND_IO;
-	pci_set_vga_state(vgadev->pdev, true, pci_bits, !!(wants & VGA_RSRC_LEGACY_MASK));
 
-	vga_irq_set_state(vgadev, true);
+	if (!vgadev->bridge_has_one_vga) {
+		flags |= PCI_VGA_STATE_CHANGE_DECODES;
+		if (wants & (VGA_RSRC_LEGACY_MEM|VGA_RSRC_NORMAL_MEM))
+			pci_bits |= PCI_COMMAND_MEMORY;
+		if (wants & (VGA_RSRC_LEGACY_IO|VGA_RSRC_NORMAL_IO))
+			pci_bits |= PCI_COMMAND_IO;
+	}
+	if (!!(wants & VGA_RSRC_LEGACY_MASK))
+		flags |= PCI_VGA_STATE_CHANGE_BRIDGE;
+
+	pci_set_vga_state(vgadev->pdev, true, pci_bits, flags);
+
+	if (!vgadev->bridge_has_one_vga) {
+		vga_irq_set_state(vgadev, true);
+	}
 	vgadev->owns |= (wants & vgadev->decodes);
 lock_them:
 	vgadev->locks |= (rsrc & VGA_RSRC_LEGACY_MASK);
@@ -267,7 +318,7 @@ static void __vga_put(struct vga_device *vgadev, unsigned int rsrc)
 {
 	unsigned int old_locks = vgadev->locks;
 
-	pr_devel("%s\n", __func__);
+	pr_debug("%s\n", __func__);
 
 	/* Update our counters, and account for equivalent legacy resources
 	 * if we decode them
@@ -400,6 +451,60 @@ bail:
 }
 EXPORT_SYMBOL(vga_put);
 
+/* Rules for using a bridge to control a VGA descendant decoding:
+   if a bridge has only one VGA descendant then it can be used
+   to control the VGA routing for that device.
+   It should always use the bridge closest to the device to control it.
+   If a bridge has a direct VGA descendant, but also have a sub-bridge
+   VGA descendant then we cannot use that bridge to control the direct VGA descendant.
+   So for every device we register, we need to iterate all its parent bridges
+   so we can invalidate any devices using them properly.
+*/
+static void vga_arbiter_check_bridge_sharing(struct vga_device *vgadev)
+{
+	struct vga_device *same_bridge_vgadev;
+	struct pci_bus *new_bus, *bus;
+	struct pci_dev *new_bridge, *bridge;
+
+	vgadev->bridge_has_one_vga = true;
+
+	if (list_empty(&vga_list))
+		return;
+
+	/* okay iterate the new devices bridge hierarachy */
+	new_bus = vgadev->pdev->bus;
+	while (new_bus) {
+		new_bridge = new_bus->self;
+
+		/* go through list of devices already registered */
+		list_for_each_entry(same_bridge_vgadev, &vga_list, list) {
+			bus = same_bridge_vgadev->pdev->bus;
+			bridge = bus->self;
+
+			/* see if the share a bridge with this device */
+			if (new_bridge == bridge) {
+				/* if their direct parent bridge is the same
+				   as any bridge of this device then it can't be used
+				   for that device */
+				same_bridge_vgadev->bridge_has_one_vga = false;
+			}
+
+			/* now iterate the previous devices bridge hierarchy */
+			/* if the new devices parent bridge is in the other devices
+			   hierarchy then we can't use it to control this device */
+			while (bus) {
+				bridge = bus->self;
+				if (bridge) {
+					if (bridge == vgadev->pdev->bus->self)
+						vgadev->bridge_has_one_vga = false;
+				}
+				bus = bus->parent;
+			}
+		}
+		new_bus = new_bus->parent;
+	}
+}
+
 /*
  * Currently, we assume that the "initial" setup of the system is
  * not sane, that is we come up with conflicting devices and let
@@ -476,9 +581,11 @@ static bool vga_arbiter_add_pci_device(struct pci_dev *pdev)
 #ifndef __ARCH_HAS_VGA_DEFAULT_DEVICE
 	if (vga_default == NULL &&
 	    ((vgadev->owns & VGA_RSRC_LEGACY_MASK) == VGA_RSRC_LEGACY_MASK))
-		vga_default = pci_dev_get(pdev);
+		vga_set_default_device(pdev);
 #endif
 
+	vga_arbiter_check_bridge_sharing(vgadev);
+
 	/* Add to the list */
 	list_add(&vgadev->list, &vga_list);
 	vga_count++;
@@ -509,10 +616,10 @@ static bool vga_arbiter_del_pci_device(struct pci_dev *pdev)
 		goto bail;
 	}
 
-	if (vga_default == pdev) {
-		pci_dev_put(vga_default);
-		vga_default = NULL;
-	}
+#ifndef __ARCH_HAS_VGA_DEFAULT_DEVICE
+	if (vga_default == pdev)
+		vga_set_default_device(NULL);
+#endif
 
 	if (vgadev->decodes & (VGA_RSRC_LEGACY_IO | VGA_RSRC_LEGACY_MEM))
 		vga_decode_count--;
@@ -537,10 +644,12 @@ bail:
 static inline void vga_update_device_decodes(struct vga_device *vgadev,
 					     int new_decodes)
 {
-	int old_decodes;
-	struct vga_device *new_vgadev, *conflict;
+	int old_decodes, decodes_removed, decodes_unlocked;
 
 	old_decodes = vgadev->decodes;
+	decodes_removed = ~new_decodes & old_decodes;
+	decodes_unlocked = vgadev->locks & decodes_removed;
+	vgadev->owns &= ~decodes_removed;
 	vgadev->decodes = new_decodes;
 
 	pr_info("vgaarb: device changed decodes: PCI:%s,olddecodes=%s,decodes=%s:owns=%s\n",
@@ -549,34 +658,26 @@ static inline void vga_update_device_decodes(struct vga_device *vgadev,
 		vga_iostate_to_str(vgadev->decodes),
 		vga_iostate_to_str(vgadev->owns));
 
-
-	/* if we own the decodes we should move them along to
-	   another card */
-	if ((vgadev->owns & old_decodes) && (vga_count > 1)) {
-		/* set us to own nothing */
-		vgadev->owns &= ~old_decodes;
-		list_for_each_entry(new_vgadev, &vga_list, list) {
-			if ((new_vgadev != vgadev) &&
-			    (new_vgadev->decodes & VGA_RSRC_LEGACY_MASK)) {
-				pr_info("vgaarb: transferring owner from PCI:%s to PCI:%s\n", pci_name(vgadev->pdev), pci_name(new_vgadev->pdev));
-				conflict = __vga_tryget(new_vgadev, VGA_RSRC_LEGACY_MASK);
-				if (!conflict)
-					__vga_put(new_vgadev, VGA_RSRC_LEGACY_MASK);
-				break;
-			}
-		}
+	/* if we removed locked decodes, lock count goes to zero, and release */
+	if (decodes_unlocked) {
+		if (decodes_unlocked & VGA_RSRC_LEGACY_IO)
+			vgadev->io_lock_cnt = 0;
+		if (decodes_unlocked & VGA_RSRC_LEGACY_MEM)
+			vgadev->mem_lock_cnt = 0;
+		__vga_put(vgadev, decodes_unlocked);
 	}
 
 	/* change decodes counter */
-	if (old_decodes != new_decodes) {
-		if (new_decodes & (VGA_RSRC_LEGACY_IO | VGA_RSRC_LEGACY_MEM))
-			vga_decode_count++;
-		else
-			vga_decode_count--;
-	}
+	if (old_decodes & VGA_RSRC_LEGACY_MASK &&
+	    !(new_decodes & VGA_RSRC_LEGACY_MASK))
+		vga_decode_count--;
+	if (!(old_decodes & VGA_RSRC_LEGACY_MASK) &&
+	    new_decodes & VGA_RSRC_LEGACY_MASK)
+		vga_decode_count++;
+	pr_debug("vgaarb: decoding count now is: %d\n", vga_decode_count);
 }
 
-void __vga_set_legacy_decoding(struct pci_dev *pdev, unsigned int decodes, bool userspace)
+static void __vga_set_legacy_decoding(struct pci_dev *pdev, unsigned int decodes, bool userspace)
 {
 	struct vga_device *vgadev;
 	unsigned long flags;
@@ -614,7 +715,7 @@ int vga_client_register(struct pci_dev *pdev, void *cookie,
 			void (*irq_set_state)(void *cookie, bool state),
 			unsigned int (*set_vga_decode)(void *cookie, bool decode))
 {
-	int ret = -1;
+	int ret = -ENODEV;
 	struct vga_device *vgadev;
 	unsigned long flags;
 
@@ -688,7 +789,7 @@ EXPORT_SYMBOL(vga_client_register);
  * the arbiter.
  */
 
-#define MAX_USER_CARDS         16
+#define MAX_USER_CARDS         CONFIG_VGA_ARB_MAX_GPUS
 #define PCI_INVALID_CARD       ((struct pci_dev *)-1UL)
 
 /*
@@ -752,7 +853,7 @@ static ssize_t vga_arb_read(struct file *file, char __user * buf,
 	 */
 	spin_lock_irqsave(&vga_lock, flags);
 
-	/* If we are targetting the default, use it */
+	/* If we are targeting the default, use it */
 	pdev = priv->target;
 	if (pdev == NULL || pdev == PCI_INVALID_CARD) {
 		spin_unlock_irqrestore(&vga_lock, flags);
@@ -830,7 +931,7 @@ static ssize_t vga_arb_write(struct file *file, const char __user * buf,
 		curr_pos += 5;
 		remaining -= 5;
 
-		pr_devel("client 0x%p called 'lock'\n", priv);
+		pr_debug("client 0x%p called 'lock'\n", priv);
 
 		if (!vga_str_to_iostate(curr_pos, remaining, &io_state)) {
 			ret_val = -EPROTO;
@@ -866,7 +967,7 @@ static ssize_t vga_arb_write(struct file *file, const char __user * buf,
 		curr_pos += 7;
 		remaining -= 7;
 
-		pr_devel("client 0x%p called 'unlock'\n", priv);
+		pr_debug("client 0x%p called 'unlock'\n", priv);
 
 		if (strncmp(curr_pos, "all", 3) == 0)
 			io_state = VGA_RSRC_LEGACY_IO | VGA_RSRC_LEGACY_MEM;
@@ -894,14 +995,20 @@ static ssize_t vga_arb_write(struct file *file, const char __user * buf,
 				uc = &priv->cards[i];
 		}
 
-		if (!uc)
-			return -EINVAL;
+		if (!uc) {
+			ret_val = -EINVAL;
+			goto done;
+		}
 
-		if (io_state & VGA_RSRC_LEGACY_IO && uc->io_cnt == 0)
-			return -EINVAL;
+		if (io_state & VGA_RSRC_LEGACY_IO && uc->io_cnt == 0) {
+			ret_val = -EINVAL;
+			goto done;
+		}
 
-		if (io_state & VGA_RSRC_LEGACY_MEM && uc->mem_cnt == 0)
-			return -EINVAL;
+		if (io_state & VGA_RSRC_LEGACY_MEM && uc->mem_cnt == 0) {
+			ret_val = -EINVAL;
+			goto done;
+		}
 
 		vga_put(pdev, io_state);
 
@@ -916,7 +1023,7 @@ static ssize_t vga_arb_write(struct file *file, const char __user * buf,
 		curr_pos += 8;
 		remaining -= 8;
 
-		pr_devel("client 0x%p called 'trylock'\n", priv);
+		pr_debug("client 0x%p called 'trylock'\n", priv);
 
 		if (!vga_str_to_iostate(curr_pos, remaining, &io_state)) {
 			ret_val = -EPROTO;
@@ -959,9 +1066,9 @@ static ssize_t vga_arb_write(struct file *file, const char __user * buf,
 
 		curr_pos += 7;
 		remaining -= 7;
-		pr_devel("client 0x%p called 'target'\n", priv);
+		pr_debug("client 0x%p called 'target'\n", priv);
 		/* if target is default */
-		if (!strncmp(buf, "default", 7))
+		if (!strncmp(curr_pos, "default", 7))
 			pdev = pci_dev_get(vga_default_device());
 		else {
 			if (!vga_pci_str_to_vars(curr_pos, remaining,
@@ -969,18 +1076,23 @@ static ssize_t vga_arb_write(struct file *file, const char __user * buf,
 				ret_val = -EPROTO;
 				goto done;
 			}
+			pr_debug("vgaarb: %s ==> %x:%x:%x.%x\n", curr_pos,
+				domain, bus, PCI_SLOT(devfn), PCI_FUNC(devfn));
 
-			pdev = pci_get_bus_and_slot(bus, devfn);
+			pdev = pci_get_domain_bus_and_slot(domain, bus, devfn);
+			pr_debug("vgaarb: pdev %p\n", pdev);
 			if (!pdev) {
-				pr_info("vgaarb: invalid PCI address!\n");
+				pr_err("vgaarb: invalid PCI address %x:%x:%x\n",
+					domain, bus, devfn);
 				ret_val = -ENODEV;
 				goto done;
 			}
 		}
 
 		vgadev = vgadev_find(pdev);
+		pr_debug("vgaarb: vgadev %p\n", vgadev);
 		if (vgadev == NULL) {
-			pr_info("vgaarb: this pci device is not a vga device\n");
+			pr_err("vgaarb: this pci device is not a vga device\n");
 			pci_dev_put(pdev);
 			ret_val = -ENODEV;
 			goto done;
@@ -998,7 +1110,8 @@ static ssize_t vga_arb_write(struct file *file, const char __user * buf,
 			}
 		}
 		if (i == MAX_USER_CARDS) {
-			pr_err("vgaarb: maximum user cards number reached!\n");
+			pr_err("vgaarb: maximum user cards (%d) number reached!\n",
+				MAX_USER_CARDS);
 			pci_dev_put(pdev);
 			/* XXX: which value to return? */
 			ret_val =  -ENOMEM;
@@ -1013,7 +1126,7 @@ static ssize_t vga_arb_write(struct file *file, const char __user * buf,
 	} else if (strncmp(curr_pos, "decodes ", 8) == 0) {
 		curr_pos += 8;
 		remaining -= 8;
-		pr_devel("vgaarb: client 0x%p called 'decodes'\n", priv);
+		pr_debug("vgaarb: client 0x%p called 'decodes'\n", priv);
 
 		if (!vga_str_to_iostate(curr_pos, remaining, &io_state)) {
 			ret_val = -EPROTO;
@@ -1042,7 +1155,7 @@ static unsigned int vga_arb_fpoll(struct file *file, poll_table * wait)
 {
 	struct vga_arb_private *priv = file->private_data;
 
-	pr_devel("%s\n", __func__);
+	pr_debug("%s\n", __func__);
 
 	if (priv == NULL)
 		return -ENODEV;
@@ -1055,12 +1168,11 @@ static int vga_arb_open(struct inode *inode, struct file *file)
 	struct vga_arb_private *priv;
 	unsigned long flags;
 
-	pr_devel("%s\n", __func__);
+	pr_debug("%s\n", __func__);
 
-	priv = kmalloc(sizeof(struct vga_arb_private), GFP_KERNEL);
+	priv = kzalloc(sizeof(*priv), GFP_KERNEL);
 	if (priv == NULL)
 		return -ENOMEM;
-	memset(priv, 0, sizeof(*priv));
 	spin_lock_init(&priv->lock);
 	file->private_data = priv;
 
@@ -1085,7 +1197,7 @@ static int vga_arb_release(struct inode *inode, struct file *file)
 	unsigned long flags;
 	int i;
 
-	pr_devel("%s\n", __func__);
+	pr_debug("%s\n", __func__);
 
 	if (priv == NULL)
 		return -ENODEV;
@@ -1096,7 +1208,7 @@ static int vga_arb_release(struct inode *inode, struct file *file)
 		uc = &priv->cards[i];
 		if (uc->pdev == NULL)
 			continue;
-		pr_devel("uc->io_cnt == %d, uc->mem_cnt == %d\n",
+		pr_debug("uc->io_cnt == %d, uc->mem_cnt == %d\n",
 			 uc->io_cnt, uc->mem_cnt);
 		while (uc->io_cnt--)
 			vga_put(uc->pdev, VGA_RSRC_LEGACY_IO);
@@ -1149,7 +1261,7 @@ static int pci_notify(struct notifier_block *nb, unsigned long action,
 	struct pci_dev *pdev = to_pci_dev(dev);
 	bool notify = false;
 
-	pr_devel("%s\n", __func__);
+	pr_debug("%s\n", __func__);
 
 	/* For now we're only intereted in devices added and removed. I didn't
 	 * test this thing here, so someone needs to double check for the
@@ -1174,6 +1286,7 @@ static const struct file_operations vga_arb_device_fops = {
 	.poll = vga_arb_fpoll,
 	.open = vga_arb_open,
 	.release = vga_arb_release,
+	.llseek = noop_llseek,
 };
 
 static struct miscdevice vga_arb_device = {
@@ -1184,6 +1297,7 @@ static int __init vga_arb_device_init(void)
 {
 	int rc;
 	struct pci_dev *pdev;
+	struct vga_device *vgadev;
 
 	rc = misc_register(&vga_arb_device);
 	if (rc < 0)
@@ -1200,6 +1314,13 @@ static int __init vga_arb_device_init(void)
 		vga_arbiter_add_pci_device(pdev);
 
 	pr_info("vgaarb: loaded\n");
+
+	list_for_each_entry(vgadev, &vga_list, list) {
+		if (vgadev->bridge_has_one_vga)
+			pr_info("vgaarb: bridge control possible %s\n", pci_name(vgadev->pdev));
+		else
+			pr_info("vgaarb: no bridge control possible %s\n", pci_name(vgadev->pdev));
+	}
 	return rc;
 }
 subsys_initcall(vga_arb_device_init);