Nouveau - Jun 2023 - [PATCH v7 0/8] PCI/VGA: Introduce is_boot_device function callback to vga_client_register

The vga_is_firmware_default() function is arch-dependent, it's probably
wrong if we simply remove the arch guard. As the VRAM BAR which contains
firmware framebuffer may move, while the lfb_base and lfb_size members of
the screen_info does not change accordingly. In short, it should take the
re-allocation of the PCI BAR into consideration.

With the observation that device drivers or video aperture helpers may
have better knowledge about which PCI bar contains the firmware fb,
which could avoid the need to iterate all of the PCI BARs. But as a PCI
function at pci/vgaarb.c, vga_is_firmware_default() is not suitable to
make such an optimization since it is loaded too early.

There are PCI display controllers that don't have a dedicated VRAM bar,
this function will lose its effectiveness in such a case. Luckily, the
device driver can provide an accurate workaround.

Therefore, this patch introduces a callback that allows the device driver
to tell the VGAARB if the device is the default boot device. Also honor
the comment: "Clients have two callback mechanisms they can use"

Sui Jingfeng (8):
  PCI/VGA: Use unsigned type for the io_state variable
  PCI/VGA: Deal only with VGA class devices
  PCI/VGA: Tidy up the code and comment format
  PCI/VGA: Replace full MIT license text with SPDX identifier
  video/aperture: Add a helper to detect if an aperture contains
    firmware FB
  PCI/VGA: Introduce is_boot_device function callback to
    vga_client_register
  drm/amdgpu: Implement the is_boot_device callback function
  drm/radeon: Implement the is_boot_device callback function

 drivers/gpu/drm/amd/amdgpu/amdgpu_device.c |  12 +-
 drivers/gpu/drm/drm_aperture.c             |  16 +++
 drivers/gpu/drm/i915/display/intel_vga.c   |   3 +-
 drivers/gpu/drm/nouveau/nouveau_vga.c      |   2 +-
 drivers/gpu/drm/radeon/radeon_device.c     |  12 +-
 drivers/pci/vgaarb.c                       | 153 +++++++++++++--------
 drivers/vfio/pci/vfio_pci_core.c           |   2 +-
 drivers/video/aperture.c                   |  29 ++++
 include/drm/drm_aperture.h                 |   2 +
 include/linux/aperture.h                   |   7 +
 include/linux/vgaarb.h                     |  35 ++---
 11 files changed, 184 insertions(+), 89 deletions(-)

-- 
2.25.1

From: Sui Jingfeng <suijingfeng at loongson.cn>

The io_state variable in the vga_arb_write() function is declared with
unsigned int type, while the vga_str_to_iostate() function takes int *
type. To keep them consistent, replace the third argument of
vga_str_to_iostate() function with the unsigned int * type.

Cc: Bjorn Helgaas <bhelgaas at google.com>
Signed-off-by: Sui Jingfeng <suijingfeng at loongson.cn>
Reviewed-by: Andi Shyti <andi.shyti at linux.intel.com>
---
 drivers/pci/vgaarb.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/pci/vgaarb.c b/drivers/pci/vgaarb.c
index 5a696078b382..c1bc6c983932 100644
--- a/drivers/pci/vgaarb.c
+++ b/drivers/pci/vgaarb.c
@@ -77,7 +77,7 @@ static const char *vga_iostate_to_str(unsigned int iostate)
 	return "none";
 }
 
-static int vga_str_to_iostate(char *buf, int str_size, int *io_state)
+static int vga_str_to_iostate(char *buf, int str_size, unsigned int *io_state)
 {
 	/* we could in theory hand out locks on IO and mem
 	 * separately to userspace but it can cause deadlocks */
-- 
2.25.1

From: Sui Jingfeng <suijingfeng at loongson.cn>

Deal only with the VGA devcie(pdev->class == 0x0300), so replace the
pci_get_subsys() function with pci_get_class(). Filter the non-PCI display
device(pdev->class != 0x0300) out. There no need to process the non-display
PCI device.

Cc: Bjorn Helgaas <bhelgaas at google.com>
Signed-off-by: Sui Jingfeng <suijingfeng at loongson.cn>
---
 drivers/pci/vgaarb.c | 22 ++++++++++++----------
 1 file changed, 12 insertions(+), 10 deletions(-)

diff --git a/drivers/pci/vgaarb.c b/drivers/pci/vgaarb.c
index c1bc6c983932..22a505e877dc 100644
--- a/drivers/pci/vgaarb.c
+++ b/drivers/pci/vgaarb.c
@@ -754,10 +754,6 @@ 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) {
@@ -1500,7 +1496,9 @@ static int pci_notify(struct notifier_block *nb, unsigned
long action,
 	struct pci_dev *pdev = to_pci_dev(dev);
 	bool notify = false;
 
-	vgaarb_dbg(dev, "%s\n", __func__);
+	/* Only deal with VGA class devices */
+	if (pdev->class != PCI_CLASS_DISPLAY_VGA << 8)
+		return 0;
 
 	/* 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
@@ -1510,6 +1508,8 @@ static int pci_notify(struct notifier_block *nb, unsigned
long action,
 	else if (action == BUS_NOTIFY_DEL_DEVICE)
 		notify = vga_arbiter_del_pci_device(pdev);
 
+	vgaarb_dbg(dev, "%s: action = %lu\n", __func__, action);
+
 	if (notify)
 		vga_arbiter_notify_clients();
 	return 0;
@@ -1534,8 +1534,8 @@ static struct miscdevice vga_arb_device = {
 
 static int __init vga_arb_device_init(void)
 {
+	struct pci_dev *pdev = NULL;
 	int rc;
-	struct pci_dev *pdev;
 
 	rc = misc_register(&vga_arb_device);
 	if (rc < 0)
@@ -1545,11 +1545,13 @@ static int __init vga_arb_device_init(void)
 
 	/* We add all PCI devices satisfying VGA class in the arbiter by
 	 * default */
-	pdev = NULL;
-	while ((pdev -		pci_get_subsys(PCI_ANY_ID, PCI_ANY_ID, PCI_ANY_ID,
-			       PCI_ANY_ID, pdev)) != NULL)
+	while (1) {
+		pdev = pci_get_class(PCI_CLASS_DISPLAY_VGA << 8, pdev);
+		if (!pdev)
+			break;
+
 		vga_arbiter_add_pci_device(pdev);
+	}
 
 	pr_info("loaded\n");
 	return rc;
-- 
2.25.1

From: Sui Jingfeng <suijingfeng at loongson.cn>

This patch replaces the leading space with a tab and removes the double
blank line, no functional change.

Cc: Bjorn Helgaas <bhelgaas at google.com>
Cc: Maarten Lankhorst <maarten.lankhorst at linux.intel.com>
Cc: Maxime Ripard <mripard at kernel.org>
Cc: Thomas Zimmermann <tzimmermann at suse.de>
Cc: David Airlie <airlied at gmail.com>
Cc: Daniel Vetter <daniel at ffwll.ch>
Signed-off-by: Sui Jingfeng <suijingfeng at loongson.cn>
Reviewed-by: Andi Shyti <andi.shyti at linux.intel.com>
---
 drivers/pci/vgaarb.c   | 108 ++++++++++++++++++++++++-----------------
 include/linux/vgaarb.h |   4 +-
 2 files changed, 65 insertions(+), 47 deletions(-)

diff --git a/drivers/pci/vgaarb.c b/drivers/pci/vgaarb.c
index 22a505e877dc..ceb914245383 100644
--- a/drivers/pci/vgaarb.c
+++ b/drivers/pci/vgaarb.c
@@ -61,7 +61,6 @@ static bool vga_arbiter_used;
 static DEFINE_SPINLOCK(vga_lock);
 static DECLARE_WAIT_QUEUE_HEAD(vga_wait_queue);
 
-
 static const char *vga_iostate_to_str(unsigned int iostate)
 {
 	/* Ignore VGA_RSRC_IO and VGA_RSRC_MEM */
@@ -79,8 +78,10 @@ static const char *vga_iostate_to_str(unsigned int iostate)
 
 static int vga_str_to_iostate(char *buf, int str_size, unsigned int *io_state)
 {
-	/* we could in theory hand out locks on IO and mem
-	 * separately to userspace but it can cause deadlocks */
+	/*
+	 * We could in theory hand out locks on IO and mem
+	 * separately to userspace but it can cause deadlocks
+	 */
 	if (strncmp(buf, "none", 4) == 0) {
 		*io_state = VGA_RSRC_NONE;
 		return 1;
@@ -99,7 +100,7 @@ static int vga_str_to_iostate(char *buf, int str_size,
unsigned int *io_state)
 	return 1;
 }
 
-/* this is only used a cookie - it should not be dereferenced */
+/* This is only used as cookie, it should not be dereferenced */
 static struct pci_dev *vga_default;
 
 /* Find somebody in our list */
@@ -193,14 +194,17 @@ int vga_remove_vgacon(struct pci_dev *pdev)
 #endif
 EXPORT_SYMBOL(vga_remove_vgacon);
 
-/* If we don't ever use VGA arb we should avoid
-   turning off anything anywhere due to old X servers getting
-   confused about the boot device not being VGA */
+/*
+ * If we don't ever use VGA arb we should avoid
+ * turning off anything anywhere due to old X servers getting
+ * confused about the boot device not being VGA
+ */
 static void vga_check_first_use(void)
 {
-	/* we should inform all GPUs in the system that
-	 * VGA arb has occurred and to try and disable resources
-	 * if they can */
+	/*
+	 * We should inform all GPUs in the system that
+	 * vgaarb has occurred and to try and disable resources if they can
+	 */
 	if (!vga_arbiter_used) {
 		vga_arbiter_used = true;
 		vga_arbiter_notify_clients();
@@ -216,7 +220,8 @@ static struct vga_device *__vga_tryget(struct vga_device
*vgadev,
 	unsigned int pci_bits;
 	u32 flags = 0;
 
-	/* Account for "normal" resources to lock. If we decode the legacy,
+	/*
+	 * Account for "normal" resources to lock. If we decode the legacy,
 	 * counterpart, we need to request it as well
 	 */
 	if ((rsrc & VGA_RSRC_NORMAL_IO) &&
@@ -236,7 +241,8 @@ static struct vga_device *__vga_tryget(struct vga_device
*vgadev,
 	if (wants == 0)
 		goto lock_them;
 
-	/* We don't need to request a legacy resource, we just enable
+	/*
+	 * We don't need to request a legacy resource, we just enable
 	 * appropriate decoding and go
 	 */
 	legacy_wants = wants & VGA_RSRC_LEGACY_MASK;
@@ -252,7 +258,8 @@ static struct vga_device *__vga_tryget(struct vga_device
*vgadev,
 		if (vgadev == conflict)
 			continue;
 
-		/* We have a possible conflict. before we go further, we must
+		/*
+		 * We have a possible conflict. before we go further, we must
 		 * check if we sit on the same bus as the conflicting device.
 		 * if we don't, then we must tie both IO and MEM resources
 		 * together since there is only a single bit controlling
@@ -263,13 +270,15 @@ static struct vga_device *__vga_tryget(struct vga_device
*vgadev,
 			lwants = VGA_RSRC_LEGACY_IO | VGA_RSRC_LEGACY_MEM;
 		}
 
-		/* Check if the guy has a lock on the resource. If he does,
+		/*
+		 * Check if the guy has a lock on the resource. If he does,
 		 * return the conflicting entry
 		 */
 		if (conflict->locks & lwants)
 			return conflict;
 
-		/* Ok, now check if it owns the resource we want.  We can
+		/*
+		 * Ok, now check if it owns the resource we want.  We can
 		 * lock resources that are not decoded, therefore a device
 		 * can own resources it doesn't decode.
 		 */
@@ -277,14 +286,16 @@ static struct vga_device *__vga_tryget(struct vga_device
*vgadev,
 		if (!match)
 			continue;
 
-		/* looks like he doesn't have a lock, we can steal
+		/*
+		 * Looks like he doesn't have a lock, we can steal
 		 * them from him
 		 */
 
 		flags = 0;
 		pci_bits = 0;
 
-		/* If we can't control legacy resources via the bridge, we
+		/*
+		 * If we can't control legacy resources via the bridge, we
 		 * also need to disable normal decoding.
 		 */
 		if (!conflict->bridge_has_one_vga) {
@@ -311,7 +322,8 @@ static struct vga_device *__vga_tryget(struct vga_device
*vgadev,
 	}
 
 enable_them:
-	/* ok dude, we got it, everybody conflicting has been disabled, let's
+	/*
+	 * Ok dude, we got it, everybody conflicting has been disabled, let's
 	 * enable us.  Mark any bits in "owns" regardless of whether we
 	 * decoded them.  We can lock resources we don't decode, therefore
 	 * we must track them via "owns".
@@ -353,7 +365,8 @@ static void __vga_put(struct vga_device *vgadev, unsigned
int rsrc)
 
 	vgaarb_dbg(dev, "%s\n", __func__);
 
-	/* Update our counters, and account for equivalent legacy resources
+	/*
+	 * Update our counters, and account for equivalent legacy resources
 	 * if we decode them
 	 */
 	if ((rsrc & VGA_RSRC_NORMAL_IO) && vgadev->io_norm_cnt > 0)
{
@@ -371,7 +384,8 @@ static void __vga_put(struct vga_device *vgadev, unsigned
int rsrc)
 	if ((rsrc & VGA_RSRC_LEGACY_MEM) && vgadev->mem_lock_cnt >
0)
 		vgadev->mem_lock_cnt--;
 
-	/* Just clear lock bits, we do lazy operations so we don't really
+	/*
+	 * Just clear lock bits, we do lazy operations so we don't really
 	 * have to bother about anything else at this point
 	 */
 	if (vgadev->io_lock_cnt == 0)
@@ -379,7 +393,8 @@ static void __vga_put(struct vga_device *vgadev, unsigned
int rsrc)
 	if (vgadev->mem_lock_cnt == 0)
 		vgadev->locks &= ~VGA_RSRC_LEGACY_MEM;
 
-	/* Kick the wait queue in case somebody was waiting if we actually
+	/*
+	 * Kick the wait queue in case somebody was waiting if we actually
 	 * released something
 	 */
 	if (old_locks != vgadev->locks)
@@ -447,8 +462,8 @@ int vga_get(struct pci_dev *pdev, unsigned int rsrc, int
interruptible)
 		if (conflict == NULL)
 			break;
 
-
-		/* We have a conflict, we wait until somebody kicks the
+		/*
+		 * We have a conflict, we wait until somebody kicks the
 		 * work queue. Currently we have one work queue that we
 		 * kick each time some resources are released, but it would
 		 * be fairly easy to have a per device one so that we only
@@ -665,7 +680,7 @@ static bool vga_is_boot_device(struct vga_device *vgadev)
 	}
 
 	/*
-	 * vgadev has neither IO nor MEM enabled.  If we haven't found any
+	 * Vgadev has neither IO nor MEM enabled.  If we haven't found any
 	 * other VGA devices, it is the best candidate so far.
 	 */
 	if (!boot_vga)
@@ -706,7 +721,7 @@ static void vga_arbiter_check_bridge_sharing(struct
vga_device *vgadev)
 			bus = same_bridge_vgadev->pdev->bus;
 			bridge = bus->self;
 
-			/* see if the share a bridge with this device */
+			/* See if the share a bridge with this device */
 			if (new_bridge == bridge) {
 				/*
 				 * If their direct parent bridge is the same
@@ -777,9 +792,10 @@ static bool vga_arbiter_add_pci_device(struct pci_dev
*pdev)
 	vgadev->decodes = VGA_RSRC_LEGACY_IO | VGA_RSRC_LEGACY_MEM |
 			  VGA_RSRC_NORMAL_IO | VGA_RSRC_NORMAL_MEM;
 
-	/* by default mark it as decoding */
+	/* By default, mark it as decoding */
 	vga_decode_count++;
-	/* Mark that we "own" resources based on our enables, we will
+	/*
+	 * Mark that we "own" resources based on our enables, we will
 	 * clear that below if the bridge isn't forwarding
 	 */
 	pci_read_config_word(pdev, PCI_COMMAND, &cmd);
@@ -860,7 +876,7 @@ static bool vga_arbiter_del_pci_device(struct pci_dev *pdev)
 	return ret;
 }
 
-/* this is called with the lock */
+/* This is called with the lock */
 static inline void vga_update_device_decodes(struct vga_device *vgadev,
 					     int new_decodes)
 {
@@ -877,7 +893,7 @@ 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 removed locked decodes, lock count goes to zero, and release */
+	/* 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;
@@ -886,7 +902,7 @@ static inline void vga_update_device_decodes(struct
vga_device *vgadev,
 		__vga_put(vgadev, decodes_unlocked);
 	}
 
-	/* change decodes counter */
+	/* Change decodes counter */
 	if (old_decodes & VGA_RSRC_LEGACY_MASK &&
 	    !(new_decodes & VGA_RSRC_LEGACY_MASK))
 		vga_decode_count--;
@@ -910,14 +926,15 @@ static void __vga_set_legacy_decoding(struct pci_dev
*pdev,
 	if (vgadev == NULL)
 		goto bail;
 
-	/* don't let userspace futz with kernel driver decodes */
+	/* Don't let userspace futz with kernel driver decodes */
 	if (userspace && vgadev->set_decode)
 		goto bail;
 
-	/* update the device decodes + counter */
+	/* Update the device decodes + counter */
 	vga_update_device_decodes(vgadev, decodes);
 
-	/* XXX if somebody is going from "doesn't decode" to
"decodes" state
+	/*
+	 * XXX if somebody is going from "doesn't decode" to
"decodes" state
 	 * here, additional care must be taken as we may have pending owner
 	 * ship of non-legacy region ...
 	 */
@@ -952,9 +969,9 @@ EXPORT_SYMBOL(vga_set_legacy_decoding);
  * @set_decode callback: If a client can disable its GPU VGA resource, it
  * will get a callback from this to set the encode/decode state.
  *
- * Rationale: we cannot disable VGA decode resources unconditionally some
single
- * GPU laptops seem to require ACPI or BIOS access to the VGA registers to
- * control things like backlights etc.  Hopefully newer multi-GPU laptops do
+ * Rationale: we cannot disable VGA decode resources unconditionally, some
+ * single GPU laptops seem to require ACPI or BIOS access to the VGA registers
+ * to control things like backlights etc. Hopefully newer multi-GPU laptops do
  * something saner, and desktops won't have any special ACPI for this. The
  * driver will get a callback when VGA arbitration is first used by userspace
  * since some older X servers have issues.
@@ -984,7 +1001,6 @@ int vga_client_register(struct pci_dev *pdev,
 bail:
 	spin_unlock_irqrestore(&vga_lock, flags);
 	return ret;
-
 }
 EXPORT_SYMBOL(vga_client_register);
 
@@ -1075,7 +1091,6 @@ static int vga_pci_str_to_vars(char *buf, int count,
unsigned int *domain,
 	int n;
 	unsigned int slot, func;
 
-
 	n = sscanf(buf, "PCI:%x:%x:%x.%x", domain, bus, &slot,
&func);
 	if (n != 4)
 		return 0;
@@ -1310,7 +1325,7 @@ static ssize_t vga_arb_write(struct file *file, const char
__user *buf,
 		curr_pos += 7;
 		remaining -= 7;
 		pr_debug("client 0x%p called 'target'\n", priv);
-		/* if target is default */
+		/* If target is default */
 		if (!strncmp(curr_pos, "default", 7))
 			pdev = pci_dev_get(vga_default_device());
 		else {
@@ -1427,7 +1442,6 @@ static int vga_arb_open(struct inode *inode, struct file
*file)
 	priv->cards[0].io_cnt = 0;
 	priv->cards[0].mem_cnt = 0;
 
-
 	return 0;
 }
 
@@ -1461,7 +1475,7 @@ static int vga_arb_release(struct inode *inode, struct
file *file)
 }
 
 /*
- * callback any registered clients to let them know we have a
+ * Callback any registered clients to let them know we have a
  * change in VGA cards
  */
 static void vga_arbiter_notify_clients(void)
@@ -1500,9 +1514,11 @@ static int pci_notify(struct notifier_block *nb, unsigned
long action,
 	if (pdev->class != PCI_CLASS_DISPLAY_VGA << 8)
 		return 0;
 
-	/* For now we're only intereted in devices added and removed. I didn't
+	/*
+	 * 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
-	 * cases of hotplugable vga cards. */
+	 * cases of hotplugable vga cards.
+	 */
 	if (action == BUS_NOTIFY_ADD_DEVICE)
 		notify = vga_arbiter_add_pci_device(pdev);
 	else if (action == BUS_NOTIFY_DEL_DEVICE)
@@ -1543,8 +1559,10 @@ static int __init vga_arb_device_init(void)
 
 	bus_register_notifier(&pci_bus_type, &pci_notifier);
 
-	/* We add all PCI devices satisfying VGA class in the arbiter by
-	 * default */
+	/*
+	 * We add all PCI devices satisfying VGA class in the arbiter by
+	 * default
+	 */
 	while (1) {
 		pdev = pci_get_class(PCI_CLASS_DISPLAY_VGA << 8, pdev);
 		if (!pdev)
diff --git a/include/linux/vgaarb.h b/include/linux/vgaarb.h
index b4b9137f9792..6d5465f8c3f2 100644
--- a/include/linux/vgaarb.h
+++ b/include/linux/vgaarb.h
@@ -96,7 +96,7 @@ static inline int vga_client_register(struct pci_dev *pdev,
 static inline int vga_get_interruptible(struct pci_dev *pdev,
 					unsigned int rsrc)
 {
-       return vga_get(pdev, rsrc, 1);
+	return vga_get(pdev, rsrc, 1);
 }
 
 /**
@@ -111,7 +111,7 @@ static inline int vga_get_interruptible(struct pci_dev
*pdev,
 static inline int vga_get_uninterruptible(struct pci_dev *pdev,
 					  unsigned int rsrc)
 {
-       return vga_get(pdev, rsrc, 0);
+	return vga_get(pdev, rsrc, 0);
 }
 
 static inline void vga_client_unregister(struct pci_dev *pdev)
-- 
2.25.1

From: Sui Jingfeng <suijingfeng at loongson.cn>

Per Documentation/process/license-rules.rst, the SPDX MIT identifier is
equivalent to including the entire MIT license text from
LICENSES/preferred/MIT.

Replace the MIT license text with the equivalent SPDX identifier.

Cc: David Airlie <airlied at gmail.com>
Cc: Daniel Vetter <daniel at ffwll.ch>
Cc: Maarten Lankhorst <maarten.lankhorst at linux.intel.com>
Cc: Maxime Ripard <mripard at kernel.org>
Cc: Thomas Zimmermann <tzimmermann at suse.de>
Signed-off-by: Sui Jingfeng <suijingfeng at loongson.cn>
Reviewed-by: Andi Shyti <andi.shyti at linux.intel.com>
---
 include/linux/vgaarb.h | 23 ++---------------------
 1 file changed, 2 insertions(+), 21 deletions(-)

diff --git a/include/linux/vgaarb.h b/include/linux/vgaarb.h
index 6d5465f8c3f2..97129a1bbb7d 100644
--- a/include/linux/vgaarb.h
+++ b/include/linux/vgaarb.h
@@ -1,3 +1,5 @@
+/* SPDX-License-Identifier: MIT */
+
 /*
  * The VGA aribiter manages VGA space routing and VGA resource decode to
  * allow multiple VGA devices to be used in a system in a safe way.
@@ -5,27 +7,6 @@
  * (C) Copyright 2005 Benjamin Herrenschmidt <benh at
kernel.crashing.org>
  * (C) Copyright 2007 Paulo R. Zanoni <przanoni at gmail.com>
  * (C) Copyright 2007, 2009 Tiago Vignatti <vignatti at freedesktop.org>
- *
- * 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.
- *
  */
 
 #ifndef LINUX_VGA_H
-- 
2.25.1

From: Sui Jingfeng <suijingfeng at loongson.cn>

This patch adds the aperture_contain_firmware_fb() function to do the
determination. Unfortunately due to the fact that apertures list will be
freed dynamically, the location and size information of the firmware fb
will be lost after dedicated drivers call
aperture_remove_conflicting_devices(),
aperture_remove_conflicting_pci_devices() or
aperture_remove_all_conflicting_devices() functions

We handle this problem by introducing two static variables which record the
firmware framebuffer's start addrness and end addrness. It assumes that the
system has only one active firmware framebuffer driver at a time.

We don't use the global structure screen_info here, because PCI resource
may get reallocated(the VRAM BAR could be moved) at kernel boot stage.

Cc: Thomas Zimmermann <tzimmermann at suse.de>
Cc: Javier Martinez Canillas <javierm at redhat.com>
Cc: Maarten Lankhorst <maarten.lankhorst at linux.intel.com>
Cc: Maxime Ripard <mripard at kernel.org>
Cc: David Airlie <airlied at gmail.com>
Cc: Daniel Vetter <daniel at ffwll.ch>
Cc: Helge Deller <deller at gmx.de>
Signed-off-by: Sui Jingfeng <suijingfeng at loongson.cn>
---
 drivers/gpu/drm/drm_aperture.c | 16 ++++++++++++++++
 drivers/video/aperture.c       | 29 +++++++++++++++++++++++++++++
 include/drm/drm_aperture.h     |  2 ++
 include/linux/aperture.h       |  7 +++++++
 4 files changed, 54 insertions(+)

diff --git a/drivers/gpu/drm/drm_aperture.c b/drivers/gpu/drm/drm_aperture.c
index 5729f3bb4398..6e5d8a08683c 100644
--- a/drivers/gpu/drm/drm_aperture.c
+++ b/drivers/gpu/drm/drm_aperture.c
@@ -190,3 +190,19 @@ int drm_aperture_remove_conflicting_pci_framebuffers(struct
pci_dev *pdev,
 	return aperture_remove_conflicting_pci_devices(pdev, req_driver->name);
 }
 EXPORT_SYMBOL(drm_aperture_remove_conflicting_pci_framebuffers);
+
+/**
+ * drm_aperture_contain_firmware_fb - Determine if a aperture contains firmware
framebuffer
+ *
+ * @base: the aperture's base address in physical memory
+ * @size: aperture size in bytes
+ *
+ * Returns:
+ * true on if there is a firmware framebuffer belong to the aperture passed in,
+ * or false otherwise.
+ */
+bool drm_aperture_contain_firmware_fb(resource_size_t base, resource_size_t
size)
+{
+	return aperture_contain_firmware_fb(base, base + size);
+}
+EXPORT_SYMBOL(drm_aperture_contain_firmware_fb);
diff --git a/drivers/video/aperture.c b/drivers/video/aperture.c
index 561be8feca96..5a5422cec669 100644
--- a/drivers/video/aperture.c
+++ b/drivers/video/aperture.c
@@ -141,6 +141,9 @@ struct aperture_range {
 static LIST_HEAD(apertures);
 static DEFINE_MUTEX(apertures_lock);
 
+static resource_size_t firm_fb_start;
+static resource_size_t firm_fb_end;
+
 static bool overlap(resource_size_t base1, resource_size_t end1,
 		    resource_size_t base2, resource_size_t end2)
 {
@@ -170,6 +173,9 @@ static int devm_aperture_acquire(struct device *dev,
 
 	mutex_lock(&apertures_lock);
 
+	firm_fb_start = base;
+	firm_fb_end = end;
+
 	list_for_each(pos, &apertures) {
 		ap = container_of(pos, struct aperture_range, lh);
 		if (overlap(base, end, ap->base, ap->base + ap->size)) {
@@ -377,3 +383,26 @@ int aperture_remove_conflicting_pci_devices(struct pci_dev
*pdev, const char *na
 
 }
 EXPORT_SYMBOL(aperture_remove_conflicting_pci_devices);
+
+/**
+ * aperture_contain_firmware_fb - Detect if the firmware framebuffer belong to
+ *                                a aperture.
+ * @ap_start: the aperture's start address in physical memory
+ * @ap_end: the aperture's end address in physical memory
+ *
+ * Returns:
+ * true on if there is a firmware framebuffer belong to the aperture passed in,
+ * or false otherwise.
+ */
+bool aperture_contain_firmware_fb(resource_size_t ap_start, resource_size_t
ap_end)
+{
+	/* No firmware framebuffer support */
+	if (!firm_fb_start || !firm_fb_end)
+		return false;
+
+	if (firm_fb_start >= ap_start && firm_fb_end <= ap_end)
+		return true;
+
+	return false;
+}
+EXPORT_SYMBOL(aperture_contain_firmware_fb);
diff --git a/include/drm/drm_aperture.h b/include/drm/drm_aperture.h
index cbe33b49fd5d..6a0b9bacb081 100644
--- a/include/drm/drm_aperture.h
+++ b/include/drm/drm_aperture.h
@@ -35,4 +35,6 @@ drm_aperture_remove_framebuffers(const struct drm_driver
*req_driver)
 							    req_driver);
 }
 
+bool drm_aperture_contain_firmware_fb(resource_size_t base, resource_size_t
size);
+
 #endif
diff --git a/include/linux/aperture.h b/include/linux/aperture.h
index 1a9a88b11584..d4dc5917c49b 100644
--- a/include/linux/aperture.h
+++ b/include/linux/aperture.h
@@ -19,6 +19,8 @@ int aperture_remove_conflicting_devices(resource_size_t base,
resource_size_t si
 int __aperture_remove_legacy_vga_devices(struct pci_dev *pdev);
 
 int aperture_remove_conflicting_pci_devices(struct pci_dev *pdev, const char
*name);
+
+bool aperture_contain_firmware_fb(resource_size_t ap_start, resource_size_t
ap_end);
 #else
 static inline int devm_aperture_acquire_for_platform_device(struct
platform_device *pdev,
 							    resource_size_t base,
@@ -42,6 +44,11 @@ static inline int
aperture_remove_conflicting_pci_devices(struct pci_dev *pdev,
 {
 	return 0;
 }
+
+static inline bool aperture_contain_firmware_fb(resource_size_t ap_start,
resource_size_t ap_end)
+{
+	return false;
+}
 #endif
 
 /**
-- 
2.25.1

From: Sui Jingfeng <suijingfeng at loongson.cn>

The vga_is_firmware_default() function is arch-dependent, it's probably
wrong if we simply remove the arch guard. As the VRAM BAR which contains
firmware framebuffer may move, while the lfb_base and lfb_size members of
the screen_info does not change accordingly. In short, it should take the
re-allocation of the PCI BAR into consideration.

With the observation that device drivers or video aperture helpers may
have better knowledge about which PCI bar contains the firmware fb,
which could avoid the need to iterate all of the PCI BARs. But as a PCI
function at pci/vgaarb.c, vga_is_firmware_default() is not suitable to
make such an optimization since it is loaded too early.

There are PCI display controllers that don't have a dedicated VRAM bar,
this function will lose its effectiveness in such a case. Luckily, the
device driver can provide an accurate workaround.

Therefore, this patch introduces a callback that allows the device driver
to tell the VGAARB if the device is the default boot device. This patch
only intends to introduce the mechanism, while the implementation is left
to the device driver authors. Also honor the comment: "Clients have two
callback mechanisms they can use"

Cc: Alex Deucher <alexander.deucher at amd.com>
Cc: Christian Konig <christian.koenig at amd.com>
Cc: Pan Xinhui <Xinhui.Pan at amd.com>
Cc: David Airlie <airlied at gmail.com>
Cc: Daniel Vetter <daniel at ffwll.ch>
Cc: Jani Nikula <jani.nikula at linux.intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen at linux.intel.com>
Cc: Rodrigo Vivi <rodrigo.vivi at intel.com>
Cc: Tvrtko Ursulin <tvrtko.ursulin at linux.intel.com>
Cc: Ben Skeggs <bskeggs at redhat.com>
Cc: Karol Herbst <kherbst at redhat.com>
Cc: Lyude Paul <lyude at redhat.com>
Cc: Bjorn Helgaas <bhelgaas at google.com>
Cc: Alex Williamson <alex.williamson at redhat.com>
Cc: Maarten Lankhorst <maarten.lankhorst at linux.intel.com>
Cc: Maxime Ripard <mripard at kernel.org>
Cc: Thomas Zimmermann <tzimmermann at suse.de>
Cc: Hawking Zhang <Hawking.Zhang at amd.com>
Cc: Mario Limonciello <mario.limonciello at amd.com>
Cc: Lijo Lazar <lijo.lazar at amd.com>
Cc: YiPeng Chai <YiPeng.Chai at amd.com>
Cc: Bokun Zhang <Bokun.Zhang at amd.com>
Cc: Likun Gao <Likun.Gao at amd.com>
Cc: Ville Syrjala <ville.syrjala at linux.intel.com>
Cc: Jason Gunthorpe <jgg at ziepe.ca>
CC: Kevin Tian <kevin.tian at intel.com>
Cc: Cornelia Huck <cohuck at redhat.com>
Cc: Yishai Hadas <yishaih at nvidia.com>
Cc: Abhishek Sahu <abhsahu at nvidia.com>
Cc: Yi Liu <yi.l.liu at intel.com>
Signed-off-by: Sui Jingfeng <suijingfeng at loongson.cn>
---
 drivers/gpu/drm/amd/amdgpu/amdgpu_device.c |  2 +-
 drivers/gpu/drm/i915/display/intel_vga.c   |  3 +--
 drivers/gpu/drm/nouveau/nouveau_vga.c      |  2 +-
 drivers/gpu/drm/radeon/radeon_device.c     |  2 +-
 drivers/pci/vgaarb.c                       | 21 ++++++++++++++++++++-
 drivers/vfio/pci/vfio_pci_core.c           |  2 +-
 include/linux/vgaarb.h                     |  8 +++++---
 7 files changed, 30 insertions(+), 10 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
index 5c7d40873ee2..7a096f2d5c16 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
@@ -3960,7 +3960,7 @@ int amdgpu_device_init(struct amdgpu_device *adev,
 	/* this will fail for cards that aren't VGA class devices, just
 	 * ignore it */
 	if ((adev->pdev->class >> 8) == PCI_CLASS_DISPLAY_VGA)
-		vga_client_register(adev->pdev, amdgpu_device_vga_set_decode);
+		vga_client_register(adev->pdev, amdgpu_device_vga_set_decode, NULL);
 
 	px = amdgpu_device_supports_px(ddev);
 
diff --git a/drivers/gpu/drm/i915/display/intel_vga.c
b/drivers/gpu/drm/i915/display/intel_vga.c
index 286a0bdd28c6..98d7d4dffe9f 100644
--- a/drivers/gpu/drm/i915/display/intel_vga.c
+++ b/drivers/gpu/drm/i915/display/intel_vga.c
@@ -115,7 +115,6 @@ intel_vga_set_decode(struct pci_dev *pdev, bool
enable_decode)
 
 int intel_vga_register(struct drm_i915_private *i915)
 {
-
 	struct pci_dev *pdev = to_pci_dev(i915->drm.dev);
 	int ret;
 
@@ -127,7 +126,7 @@ int intel_vga_register(struct drm_i915_private *i915)
 	 * then we do not take part in VGA arbitration and the
 	 * vga_client_register() fails with -ENODEV.
 	 */
-	ret = vga_client_register(pdev, intel_vga_set_decode);
+	ret = vga_client_register(pdev, intel_vga_set_decode, NULL);
 	if (ret && ret != -ENODEV)
 		return ret;
 
diff --git a/drivers/gpu/drm/nouveau/nouveau_vga.c
b/drivers/gpu/drm/nouveau/nouveau_vga.c
index f8bf0ec26844..162b4f4676c7 100644
--- a/drivers/gpu/drm/nouveau/nouveau_vga.c
+++ b/drivers/gpu/drm/nouveau/nouveau_vga.c
@@ -92,7 +92,7 @@ nouveau_vga_init(struct nouveau_drm *drm)
 		return;
 	pdev = to_pci_dev(dev->dev);
 
-	vga_client_register(pdev, nouveau_vga_set_decode);
+	vga_client_register(pdev, nouveau_vga_set_decode, NULL);
 
 	/* don't register Thunderbolt eGPU with vga_switcheroo */
 	if (pci_is_thunderbolt_attached(pdev))
diff --git a/drivers/gpu/drm/radeon/radeon_device.c
b/drivers/gpu/drm/radeon/radeon_device.c
index afbb3a80c0c6..71f2ff39d6a1 100644
--- a/drivers/gpu/drm/radeon/radeon_device.c
+++ b/drivers/gpu/drm/radeon/radeon_device.c
@@ -1425,7 +1425,7 @@ int radeon_device_init(struct radeon_device *rdev,
 	/* if we have > 1 VGA cards, then disable the radeon VGA resources */
 	/* this will fail for cards that aren't VGA class devices, just
 	 * ignore it */
-	vga_client_register(rdev->pdev, radeon_vga_set_decode);
+	vga_client_register(rdev->pdev, radeon_vga_set_decode, NULL);
 
 	if (rdev->flags & RADEON_IS_PX)
 		runtime = true;
diff --git a/drivers/pci/vgaarb.c b/drivers/pci/vgaarb.c
index ceb914245383..c574898380f0 100644
--- a/drivers/pci/vgaarb.c
+++ b/drivers/pci/vgaarb.c
@@ -53,6 +53,7 @@ struct vga_device {
 	bool bridge_has_one_vga;
 	bool is_firmware_default;	/* device selected by firmware */
 	unsigned int (*set_decode)(struct pci_dev *pdev, bool decode);
+	bool (*is_boot_device)(struct pci_dev *pdev);
 };
 
 static LIST_HEAD(vga_list);
@@ -969,6 +970,10 @@ EXPORT_SYMBOL(vga_set_legacy_decoding);
  * @set_decode callback: If a client can disable its GPU VGA resource, it
  * will get a callback from this to set the encode/decode state.
  *
+ * @is_boot_device: callback to the device driver, query if a client is the
+ * default boot device, as the device driver typically has better knowledge
+ * if specific device is the boot device. But this callback is optional.
+ *
  * Rationale: we cannot disable VGA decode resources unconditionally, some
  * single GPU laptops seem to require ACPI or BIOS access to the VGA registers
  * to control things like backlights etc. Hopefully newer multi-GPU laptops do
@@ -984,7 +989,8 @@ EXPORT_SYMBOL(vga_set_legacy_decoding);
  * Returns: 0 on success, -1 on failure
  */
 int vga_client_register(struct pci_dev *pdev,
-		unsigned int (*set_decode)(struct pci_dev *pdev, bool decode))
+		unsigned int (*set_decode)(struct pci_dev *pdev, bool decode),
+		bool (*is_boot_device)(struct pci_dev *pdev))
 {
 	int ret = -ENODEV;
 	struct vga_device *vgadev;
@@ -996,6 +1002,7 @@ int vga_client_register(struct pci_dev *pdev,
 		goto bail;
 
 	vgadev->set_decode = set_decode;
+	vgadev->is_boot_device = is_boot_device;
 	ret = 0;
 
 bail:
@@ -1523,6 +1530,18 @@ static int pci_notify(struct notifier_block *nb, unsigned
long action,
 		notify = vga_arbiter_add_pci_device(pdev);
 	else if (action == BUS_NOTIFY_DEL_DEVICE)
 		notify = vga_arbiter_del_pci_device(pdev);
+	else if (action == BUS_NOTIFY_BOUND_DRIVER) {
+		struct vga_device *vgadev = vgadev_find(pdev);
+		bool boot_dev = false;
+
+		if (vgadev && vgadev->is_boot_device)
+			boot_dev = vgadev->is_boot_device(pdev);
+
+		if (boot_dev) {
+			vgaarb_info(&pdev->dev, "Set as boot device (dictated by
driver)\n");
+			vga_set_default_device(pdev);
+		}
+	}
 
 	vgaarb_dbg(dev, "%s: action = %lu\n", __func__, action);
 
diff --git a/drivers/vfio/pci/vfio_pci_core.c b/drivers/vfio/pci/vfio_pci_core.c
index a5ab416cf476..2a8873a330ba 100644
--- a/drivers/vfio/pci/vfio_pci_core.c
+++ b/drivers/vfio/pci/vfio_pci_core.c
@@ -2067,7 +2067,7 @@ static int vfio_pci_vga_init(struct vfio_pci_core_device
*vdev)
 	if (ret)
 		return ret;
 
-	ret = vga_client_register(pdev, vfio_pci_set_decode);
+	ret = vga_client_register(pdev, vfio_pci_set_decode, NULL);
 	if (ret)
 		return ret;
 	vga_set_legacy_decoding(pdev, vfio_pci_set_decode(pdev, false));
diff --git a/include/linux/vgaarb.h b/include/linux/vgaarb.h
index 97129a1bbb7d..dfde5a6ba55a 100644
--- a/include/linux/vgaarb.h
+++ b/include/linux/vgaarb.h
@@ -33,7 +33,8 @@ struct pci_dev *vga_default_device(void);
 void vga_set_default_device(struct pci_dev *pdev);
 int vga_remove_vgacon(struct pci_dev *pdev);
 int vga_client_register(struct pci_dev *pdev,
-		unsigned int (*set_decode)(struct pci_dev *pdev, bool state));
+		unsigned int (*set_decode)(struct pci_dev *pdev, bool state),
+		bool (*is_boot_device)(struct pci_dev *pdev));
 #else /* CONFIG_VGA_ARB */
 static inline void vga_set_legacy_decoding(struct pci_dev *pdev,
 		unsigned int decodes)
@@ -59,7 +60,8 @@ static inline int vga_remove_vgacon(struct pci_dev *pdev)
 	return 0;
 }
 static inline int vga_client_register(struct pci_dev *pdev,
-		unsigned int (*set_decode)(struct pci_dev *pdev, bool state))
+		unsigned int (*set_decode)(struct pci_dev *pdev, bool state),
+		bool (*is_boot_device)(struct pci_dev *pdev))
 {
 	return 0;
 }
@@ -97,7 +99,7 @@ static inline int vga_get_uninterruptible(struct pci_dev
*pdev,
 
 static inline void vga_client_unregister(struct pci_dev *pdev)
 {
-	vga_client_register(pdev, NULL);
+	vga_client_register(pdev, NULL, NULL);
 }
 
 #endif /* LINUX_VGA_H */
-- 
2.25.1

From: Sui Jingfeng <suijingfeng at loongson.cn>

[why]

The vga_is_firmware_default() defined in drivers/pci/vgaarb.c is
arch-dependent, it's a dummy on non-x86 architectures currently.
This made VGAARB lost an important condition for the arbitration.
It could still be wrong even if we remove the #ifdef and #endif guards.
because the PCI bar will move (resource re-allocation).

[how]

The device that owns the firmware framebuffer should be the default boot
device. This patch adds an arch-independent function to enforce this rule.
The vgaarb subsystem will call back to amdgpu_is_boot_device() function
when drm/amdgpu is successfully bound to an AMDGPU device.

Cc: Alex Deucher <alexander.deucher at amd.com>
Cc: Christian Konig <christian.koenig at amd.com>
Cc: Pan Xinhui <Xinhui.Pan at amd.com>
Cc: David Airlie <airlied at gmail.com>
Cc: Daniel Vetter <daniel at ffwll.ch>
Cc: Hawking Zhang <Hawking.Zhang at amd.com>
Cc: Mario Limonciello <mario.limonciello at amd.com>
Cc: Lijo Lazar <lijo.lazar at amd.com>
Cc: YiPeng Chai <YiPeng.Chai at amd.com>
Cc: Bokun Zhang <Bokun.Zhang at amd.com>
CC: Likun Gao <Likun.Gao at amd.com>
Signed-off-by: Sui Jingfeng <suijingfeng at loongson.cn>
---
 drivers/gpu/drm/amd/amdgpu/amdgpu_device.c | 12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
index 7a096f2d5c16..77624e8062d5 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
@@ -3560,6 +3560,15 @@ static const struct attribute *amdgpu_dev_attributes[] =
{
 	NULL
 };
 
+static bool amdgpu_is_boot_device(struct pci_dev *pdev)
+{
+	struct drm_device *dev = pci_get_drvdata(pdev);
+	struct amdgpu_device *adev = drm_to_adev(dev);
+	struct amdgpu_gmc *gmc = &adev->gmc;
+
+	return drm_aperture_contain_firmware_fb(gmc->aper_base, gmc->aper_size);
+}
+
 /**
  * amdgpu_device_init - initialize the driver
  *
@@ -3960,7 +3969,8 @@ int amdgpu_device_init(struct amdgpu_device *adev,
 	/* this will fail for cards that aren't VGA class devices, just
 	 * ignore it */
 	if ((adev->pdev->class >> 8) == PCI_CLASS_DISPLAY_VGA)
-		vga_client_register(adev->pdev, amdgpu_device_vga_set_decode, NULL);
+		vga_client_register(adev->pdev, amdgpu_device_vga_set_decode,
+				    amdgpu_is_boot_device);
 
 	px = amdgpu_device_supports_px(ddev);
 
-- 
2.25.1

From: Sui Jingfeng <suijingfeng at loongson.cn>

[why]

The vga_is_firmware_default() defined in drivers/pci/vgaarb.c is
arch-dependent, it's a dummy on non-x86 architectures currently.
This made VGAARB lost an important condition for the arbitration.
It could still be wrong even if we remove the #ifdef and #endif guards.
because the PCI bar will move (resource re-allocation).

[how]

The device that owns the firmware framebuffer should be the default boot
device. This patch adds an arch-independent function to enforce this rule.
The vgaarb subsystem will call back to radeon_is_boot_device() function
when drm/radeon is successfully bound to a radeon GPU device.

Cc: Alex Deucher <alexander.deucher at amd.com>
Cc: Christian Konig <christian.koenig at amd.com>
Cc: Pan Xinhui <Xinhui.Pan at amd.com>
Cc: David Airlie <airlied at gmail.com>
Cc: Daniel Vetter <daniel at ffwll.ch>
Signed-off-by: Sui Jingfeng <suijingfeng at loongson.cn>
---
 drivers/gpu/drm/radeon/radeon_device.c | 12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/radeon/radeon_device.c
b/drivers/gpu/drm/radeon/radeon_device.c
index 71f2ff39d6a1..afb49000830c 100644
--- a/drivers/gpu/drm/radeon/radeon_device.c
+++ b/drivers/gpu/drm/radeon/radeon_device.c
@@ -34,6 +34,7 @@
 #include <linux/vga_switcheroo.h>
 #include <linux/vgaarb.h>
 
+#include <drm/drm_aperture.h>
 #include <drm/drm_cache.h>
 #include <drm/drm_crtc_helper.h>
 #include <drm/drm_device.h>
@@ -1263,6 +1264,15 @@ static const struct vga_switcheroo_client_ops
radeon_switcheroo_ops = {
 	.can_switch = radeon_switcheroo_can_switch,
 };
 
+static bool radeon_is_boot_device(struct pci_dev *pdev)
+{
+	struct drm_device *dev = pci_get_drvdata(pdev);
+	struct radeon_device *rdev = dev->dev_private;
+	struct radeon_mc *gmc = &rdev->mc;
+
+	return drm_aperture_contain_firmware_fb(gmc->aper_base, gmc->aper_size);
+}
+
 /**
  * radeon_device_init - initialize the driver
  *
@@ -1425,7 +1435,7 @@ int radeon_device_init(struct radeon_device *rdev,
 	/* if we have > 1 VGA cards, then disable the radeon VGA resources */
 	/* this will fail for cards that aren't VGA class devices, just
 	 * ignore it */
-	vga_client_register(rdev->pdev, radeon_vga_set_decode, NULL);
+	vga_client_register(rdev->pdev, radeon_vga_set_decode,
radeon_is_boot_device);
 
 	if (rdev->flags & RADEON_IS_PX)
 		runtime = true;
-- 
2.25.1

Hi,

On 2023/6/13 11:01, Sui Jingfeng wrote:
> From: Sui Jingfeng <suijingfeng at loongson.cn>
>
> Deal only with the VGA devcie(pdev->class == 0x0300), so replace the
> pci_get_subsys() function with pci_get_class(). Filter the non-PCI display
> device(pdev->class != 0x0300) out. There no need to process the
non-display
> PCI device.
>
> Cc: Bjorn Helgaas <bhelgaas at google.com>
> Signed-off-by: Sui Jingfeng <suijingfeng at loongson.cn>
> ---
>   drivers/pci/vgaarb.c | 22 ++++++++++++----------
>   1 file changed, 12 insertions(+), 10 deletions(-)
>
> diff --git a/drivers/pci/vgaarb.c b/drivers/pci/vgaarb.c
> index c1bc6c983932..22a505e877dc 100644
> --- a/drivers/pci/vgaarb.c
> +++ b/drivers/pci/vgaarb.c
> @@ -754,10 +754,6 @@ 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;
> -
Hi, here is probably a bug fixing.

For an example, nvidia render only GPU typically has 0x0380.

at its PCI class number, but? render only GPU should not participate in 
the arbitration.

As it shouldn't snoop the legacy fixed VGA address.

It(render only GPU) can not display anything.


But 0x0380 >> 8 = 0x03, the filter? failed.

>   	/* Allocate structure */
>   	vgadev = kzalloc(sizeof(struct vga_device), GFP_KERNEL);
>   	if (vgadev == NULL) {
> @@ -1500,7 +1496,9 @@ static int pci_notify(struct notifier_block *nb,
unsigned long action,
>   	struct pci_dev *pdev = to_pci_dev(dev);
>   	bool notify = false;
>   
> -	vgaarb_dbg(dev, "%s\n", __func__);
> +	/* Only deal with VGA class devices */
> +	if (pdev->class != PCI_CLASS_DISPLAY_VGA << 8)
> +		return 0;
So here we only care 0x0300, my initial intent is to make an optimization,

nowadays sane display graphic card should all has 0x0300 as its PCI 
class number, is this complete right?

```

#define PCI_BASE_CLASS_DISPLAY??? ??? 0x03
#define PCI_CLASS_DISPLAY_VGA??? ??? 0x0300
#define PCI_CLASS_DISPLAY_XGA??? ??? 0x0301
#define PCI_CLASS_DISPLAY_3D??? ??? 0x0302
#define PCI_CLASS_DISPLAY_OTHER??? ??? 0x0380

```

Any ideas ?
>   	/* 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
> @@ -1510,6 +1508,8 @@ static int pci_notify(struct notifier_block *nb,
unsigned long action,
>   	else if (action == BUS_NOTIFY_DEL_DEVICE)
>   		notify = vga_arbiter_del_pci_device(pdev);
>   
> +	vgaarb_dbg(dev, "%s: action = %lu\n", __func__, action);
> +
>   	if (notify)
>   		vga_arbiter_notify_clients();
>   	return 0;
> @@ -1534,8 +1534,8 @@ static struct miscdevice vga_arb_device = {
>   
>   static int __init vga_arb_device_init(void)
>   {
> +	struct pci_dev *pdev = NULL;
>   	int rc;
> -	struct pci_dev *pdev;
>   
>   	rc = misc_register(&vga_arb_device);
>   	if (rc < 0)
> @@ -1545,11 +1545,13 @@ static int __init vga_arb_device_init(void)
>   
>   	/* We add all PCI devices satisfying VGA class in the arbiter by
>   	 * default */
> -	pdev = NULL;
> -	while ((pdev > -		pci_get_subsys(PCI_ANY_ID, PCI_ANY_ID, PCI_ANY_ID,
> -			       PCI_ANY_ID, pdev)) != NULL)
> +	while (1) {
> +		pdev = pci_get_class(PCI_CLASS_DISPLAY_VGA << 8, pdev);
> +		if (!pdev)
> +			break;
> +
>   		vga_arbiter_add_pci_device(pdev);
> +	}
>   
>   	pr_info("loaded\n");
>   	return rc;
-- 
Jingfeng

On Tue, 13 Jun 2023, Sui Jingfeng wrote:
> Deal only with the VGA devcie(pdev->class == 0x0300), so replace the
 Typo here: s/devcie/device/.
> pci_get_subsys() function with pci_get_class(). Filter the non-PCI display
> device(pdev->class != 0x0300) out. There no need to process the
non-display
> PCI device.
 I've only come across this patch series now.  Without diving into what 
this code actually does I have just one question as a matter of interest.
> diff --git a/drivers/pci/vgaarb.c b/drivers/pci/vgaarb.c
> index c1bc6c983932..22a505e877dc 100644
> --- a/drivers/pci/vgaarb.c
> +++ b/drivers/pci/vgaarb.c
> @@ -1500,7 +1496,9 @@ static int pci_notify(struct notifier_block *nb,
unsigned long action,
>  	struct pci_dev *pdev = to_pci_dev(dev);
>  	bool notify = false;
>  
> -	vgaarb_dbg(dev, "%s\n", __func__);
> +	/* Only deal with VGA class devices */
> +	if (pdev->class != PCI_CLASS_DISPLAY_VGA << 8)
> +		return 0;
 Hmm, shouldn't this also handle PCI_CLASS_NOT_DEFINED_VGA?  As far as I 
know it is the equivalent of PCI_CLASS_DISPLAY_VGA for PCI <= 2.0 devices 
that were implemented before the idea of PCI device classes has developed 
into its current form.  I may have such a VGA device somewhere.

  Maciej