[PATCH v9 00/11] vgaarb: Rework default VGA device selection

[PATCH v9 00/11] vgaarb: Rework default VGA device selection

[Bjorn Helgaas]

From: Bjorn Helgaas <bhelgaas@google.com>

Current default VGA device selection fails in some cases because part of it
is done in the vga_arb_device_init() subsys_initcall, and some arches
enumerate PCI devices in pcibios_init(), which runs *after* that.

The big change from the v8 posting is that this moves vgaarb.c from
drivers/gpu/vga to drivers/pci because it really has nothing to do with
GPUs or DRM.

For example:

  - On BMC system, the AST2500 bridge [1a03:1150] does not implement
    PCI_BRIDGE_CTL_VGA.  This is perfectly legal but means the legacy VGA
    resources won't reach downstream devices unless they're included in the
    usual bridge windows.

  - vga_arb_select_default_device() will set a device below such a bridge
    as the default VGA device as long as it has PCI_COMMAND_IO and
    PCI_COMMAND_MEMORY enabled.

  - vga_arbiter_add_pci_device() is called for every VGA device, either at
    boot-time or at hot-add time, and it will also set the device as the
    default VGA device, but ONLY if all bridges leading to it implement
    PCI_BRIDGE_CTL_VGA.

  - This difference between vga_arb_select_default_device() and
    vga_arbiter_add_pci_device() means that a device below an AST2500 or
    similar bridge can only be set as the default if it is enumerated
    before vga_arb_device_init().

  - On ACPI-based systems, PCI devices are enumerated by acpi_init(), which
    runs before vga_arb_device_init().

  - On non-ACPI systems, like on MIPS system, they are enumerated by
    pcibios_init(), which typically runs *after* vga_arb_device_init().

This series consolidates all the default VGA device selection in
vga_arbiter_add_pci_device(), which is always called after enumerating a
PCI device.

Almost all the work here is Huacai's.  I restructured it a little bit and
added a few trivial patches on top.

Bjorn

Version history:
V0 original implementation as final quirk to set default device.
https://lore.kernel.org/r/20210514080025.1828197-6-chenhuacai@loongson.cn

V1 rework vgaarb to do all default device selection in
vga_arbiter_add_pci_device().
https://lore.kernel.org/r/20210705100503.1120643-1-chenhuacai@loongson.cn

V2 move arbiter to PCI subsystem, fix nits.
https://lore.kernel.org/r/20210722212920.347118-1-helgaas@kernel.org

V3 rewrite the commit log of the last patch (which is also summarized
by Bjorn).
https://lore.kernel.org/r/20210820100832.663931-1-chenhuacai@loongson.cn

V4 split the last patch to two steps.
https://lore.kernel.org/r/20210827083129.2781420-1-chenhuacai@loongson.cn

V5 split Patch-9 again and sort the patches.
https://lore.kernel.org/r/20210911093056.1555274-1-chenhuacai@loongson.cn

V6 split Patch-5 again and sort the patches again.
https://lore.kernel.org/r/20210916082941.3421838-1-chenhuacai@loongson.cn

V7 stop moving vgaarb to drivers/pci because of ordering issues with
misc_init().
https://lore.kernel.org/r/20211015061512.2941859-1-chenhuacai@loongson.cn
https://lore.kernel.org/r/CAAhV-H7FhAjM-Ha42Z1dLrE4PvC9frfyeU27KHWcyWKkMftEsA@mail.gmail.com

V8 expand commit logs, rework boot VGA device selection
https://lore.kernel.org/r/20220106000658.243509-1-helgaas@kernel.org

V9 (this posting) move to drivers/pci, resolve initcall ordering, rename
vga_is_framebuffer_device() to vga_is_firmware_default()

Bjorn Helgaas (5):
  PCI/VGA: Move vgaarb to drivers/pci
  PCI/VGA: Factor out vga_select_framebuffer_device()
  PCI/VGA: Remove empty vga_arb_device_card_gone()
  PCI/VGA: Use unsigned format string to print lock counts
  PCI/VGA: Replace full MIT license text with SPDX identifier

Huacai Chen (6):
  PCI/VGA: Move vga_arb_integrated_gpu() earlier in file
  PCI/VGA: Factor out default VGA device selection
  PCI/VGA: Move firmware default device detection to ADD_DEVICE path
  PCI/VGA: Move non-legacy VGA detection to ADD_DEVICE path
  PCI/VGA: Move disabled VGA device detection to ADD_DEVICE path
  PCI/VGA: Log bridge control messages when adding devices

 drivers/gpu/vga/Kconfig           |  19 --
 drivers/gpu/vga/Makefile          |   1 -
 drivers/pci/Kconfig               |  19 ++
 drivers/pci/Makefile              |   1 +
 drivers/{gpu/vga => pci}/vgaarb.c | 313 +++++++++++++++---------------
 5 files changed, 175 insertions(+), 178 deletions(-)
 rename drivers/{gpu/vga => pci}/vgaarb.c (90%)

-- 
2.25.1

[PATCH v9 01/11] PCI/VGA: Move vgaarb to drivers/pci

[Bjorn Helgaas]

From: Bjorn Helgaas <bhelgaas@google.com>

The VGA arbiter is really PCI-specific and doesn't depend on any GPU
things.  Move it to the PCI subsystem.

Note that misc_init() must be called before vga_arb_device_init().  These
are both subsys_initcalls, so this ordering depends on the link order,
which is determined by drivers/Makefile:

  obj-y += pci/
  obj-y += char/        <-- misc_init()
  obj-y += gpu/         <-- vga_arb_device_init() (before this commit)

The drivers/pci/ subsys_initcalls are called *before* misc_init(), so
convert vga_arb_device_init() to subsys_initcall_sync(), which is called
after *all* subsys_initcalls.

Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
---
 drivers/gpu/vga/Kconfig           | 19 -------------------
 drivers/gpu/vga/Makefile          |  1 -
 drivers/pci/Kconfig               | 19 +++++++++++++++++++
 drivers/pci/Makefile              |  1 +
 drivers/{gpu/vga => pci}/vgaarb.c |  2 +-
 5 files changed, 21 insertions(+), 21 deletions(-)
 rename drivers/{gpu/vga => pci}/vgaarb.c (99%)

diff --git a/drivers/gpu/vga/Kconfig b/drivers/gpu/vga/Kconfig
index 1ad4c4ef0b5e..eb8b14ab22c3 100644
--- a/drivers/gpu/vga/Kconfig
+++ b/drivers/gpu/vga/Kconfig
@@ -1,23 +1,4 @@
 # SPDX-License-Identifier: GPL-2.0-only
-config VGA_ARB
-	bool "VGA Arbitration" if EXPERT
-	default y
-	depends on (PCI && !S390)
-	help
-	  Some "legacy" VGA devices implemented on PCI typically have the same
-	  hard-decoded addresses as they did on ISA. When multiple PCI devices
-	  are accessed at same time they need some kind of coordination. Please
-	  see Documentation/gpu/vgaarbiter.rst for more details. Select this to
-	  enable VGA arbiter.
-
-config VGA_ARB_MAX_GPUS
-	int "Maximum number of GPUs"
-	default 16
-	depends on VGA_ARB
-	help
-	  Reserves space in the kernel to maintain resource locking for
-	  multiple GPUS.  The overhead for each GPU is very small.
-
 config VGA_SWITCHEROO
 	bool "Laptop Hybrid Graphics - GPU switching support"
 	depends on X86
diff --git a/drivers/gpu/vga/Makefile b/drivers/gpu/vga/Makefile
index e92064442d60..9800620deda3 100644
--- a/drivers/gpu/vga/Makefile
+++ b/drivers/gpu/vga/Makefile
@@ -1,3 +1,2 @@
 # SPDX-License-Identifier: GPL-2.0-only
-obj-$(CONFIG_VGA_ARB)  += vgaarb.o
 obj-$(CONFIG_VGA_SWITCHEROO) += vga_switcheroo.o
diff --git a/drivers/pci/Kconfig b/drivers/pci/Kconfig
index d98fafdd0f99..133c73207782 100644
--- a/drivers/pci/Kconfig
+++ b/drivers/pci/Kconfig
@@ -252,6 +252,25 @@ config PCIE_BUS_PEER2PEER
 
 endchoice
 
+config VGA_ARB
+	bool "VGA Arbitration" if EXPERT
+	default y
+	depends on (PCI && !S390)
+	help
+	  Some "legacy" VGA devices implemented on PCI typically have the same
+	  hard-decoded addresses as they did on ISA. When multiple PCI devices
+	  are accessed at same time they need some kind of coordination. Please
+	  see Documentation/gpu/vgaarbiter.rst for more details. Select this to
+	  enable VGA arbiter.
+
+config VGA_ARB_MAX_GPUS
+	int "Maximum number of GPUs"
+	default 16
+	depends on VGA_ARB
+	help
+	  Reserves space in the kernel to maintain resource locking for
+	  multiple GPUS.  The overhead for each GPU is very small.
+
 source "drivers/pci/hotplug/Kconfig"
 source "drivers/pci/controller/Kconfig"
 source "drivers/pci/endpoint/Kconfig"
diff --git a/drivers/pci/Makefile b/drivers/pci/Makefile
index 37be95adf169..0da6b1ebc694 100644
--- a/drivers/pci/Makefile
+++ b/drivers/pci/Makefile
@@ -30,6 +30,7 @@ obj-$(CONFIG_PCI_PF_STUB)	+= pci-pf-stub.o
 obj-$(CONFIG_PCI_ECAM)		+= ecam.o
 obj-$(CONFIG_PCI_P2PDMA)	+= p2pdma.o
 obj-$(CONFIG_XEN_PCIDEV_FRONTEND) += xen-pcifront.o
+obj-$(CONFIG_VGA_ARB)		+= vgaarb.o
 
 # Endpoint library must be initialized before its users
 obj-$(CONFIG_PCI_ENDPOINT)	+= endpoint/
diff --git a/drivers/gpu/vga/vgaarb.c b/drivers/pci/vgaarb.c
similarity index 99%
rename from drivers/gpu/vga/vgaarb.c
rename to drivers/pci/vgaarb.c
index 569930552957..8320385a487b 100644
--- a/drivers/gpu/vga/vgaarb.c
+++ b/drivers/pci/vgaarb.c
@@ -1564,4 +1564,4 @@ static int __init vga_arb_device_init(void)
 	pr_info("loaded\n");
 	return rc;
 }
-subsys_initcall(vga_arb_device_init);
+subsys_initcall_sync(vga_arb_device_init);
-- 
2.25.1

[PATCH v9 02/11] PCI/VGA: Move vga_arb_integrated_gpu() earlier in file

[Bjorn Helgaas]

From: Huacai Chen <chenhuacai@loongson.cn>

Move vga_arb_integrated_gpu() earlier in file to prepare for future patch.
No functional change intended.

[bhelgaas: pull #ifdefs inside function]
Link: https://lore.kernel.org/r/20211015061512.2941859-3-chenhuacai@loongson.cn
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
---
 drivers/pci/vgaarb.c | 25 +++++++++++--------------
 1 file changed, 11 insertions(+), 14 deletions(-)

diff --git a/drivers/pci/vgaarb.c b/drivers/pci/vgaarb.c
index 8320385a487b..6c57ffb77770 100644
--- a/drivers/pci/vgaarb.c
+++ b/drivers/pci/vgaarb.c
@@ -565,6 +565,17 @@ void vga_put(struct pci_dev *pdev, unsigned int rsrc)
 }
 EXPORT_SYMBOL(vga_put);
 
+static bool vga_arb_integrated_gpu(struct device *dev)
+{
+#if defined(CONFIG_ACPI)
+	struct acpi_device *adev = ACPI_COMPANION(dev);
+
+	return adev && !strcmp(acpi_device_hid(adev), ACPI_VIDEO_HID);
+#else
+	return false;
+#endif
+}
+
 /*
  * 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
@@ -1430,20 +1441,6 @@ static struct miscdevice vga_arb_device = {
 	MISC_DYNAMIC_MINOR, "vga_arbiter", &vga_arb_device_fops
 };
 
-#if defined(CONFIG_ACPI)
-static bool vga_arb_integrated_gpu(struct device *dev)
-{
-	struct acpi_device *adev = ACPI_COMPANION(dev);
-
-	return adev && !strcmp(acpi_device_hid(adev), ACPI_VIDEO_HID);
-}
-#else
-static bool vga_arb_integrated_gpu(struct device *dev)
-{
-	return false;
-}
-#endif
-
 static void __init vga_arb_select_default_device(void)
 {
 	struct pci_dev *pdev, *found = NULL;
-- 
2.25.1

[PATCH v9 03/11] PCI/VGA: Factor out vga_select_framebuffer_device()

[Bjorn Helgaas]

From: Bjorn Helgaas <bhelgaas@google.com>

On x86 and ia64, if a VGA device BARs include a framebuffer reported by
platform firmware, we select the device as the default VGA device.  Factor
this code to a separate function.  No functional change intended.

Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Cc: Bruno Prémont <bonbons@linux-vserver.org>
---
 drivers/pci/vgaarb.c | 99 ++++++++++++++++++++++++--------------------
 1 file changed, 53 insertions(+), 46 deletions(-)

diff --git a/drivers/pci/vgaarb.c b/drivers/pci/vgaarb.c
index 6c57ffb77770..3f8fead49197 100644
--- a/drivers/pci/vgaarb.c
+++ b/drivers/pci/vgaarb.c
@@ -565,6 +565,58 @@ void vga_put(struct pci_dev *pdev, unsigned int rsrc)
 }
 EXPORT_SYMBOL(vga_put);
 
+static void __init vga_select_framebuffer_device(struct pci_dev *pdev)
+{
+#if defined(CONFIG_X86) || defined(CONFIG_IA64)
+	struct device *dev = &pdev->dev;
+	u64 base = screen_info.lfb_base;
+	u64 size = screen_info.lfb_size;
+	u64 limit;
+	resource_size_t start, end;
+	unsigned long flags;
+	int i;
+
+	/* Select the device owning the boot framebuffer if there is one */
+
+	if (screen_info.capabilities & VIDEO_CAPABILITY_64BIT_BASE)
+		base |= (u64)screen_info.ext_lfb_base << 32;
+
+	limit = base + size;
+
+	/*
+	 * Override vga_arbiter_add_pci_device()'s I/O based detection
+	 * as it may take the wrong device (e.g. on Apple system under
+	 * EFI).
+	 *
+	 * Select the device owning the boot framebuffer if there is
+	 * one.
+	 */
+
+	/* Does firmware framebuffer belong to us? */
+	for (i = 0; i < DEVICE_COUNT_RESOURCE; i++) {
+		flags = pci_resource_flags(pdev, i);
+
+		if ((flags & IORESOURCE_MEM) == 0)
+			continue;
+
+		start = pci_resource_start(pdev, i);
+		end  = pci_resource_end(pdev, i);
+
+		if (!start || !end)
+			continue;
+
+		if (base < start || limit >= end)
+			continue;
+
+		if (!vga_default_device())
+			vgaarb_info(dev, "setting as boot device\n");
+		else if (pdev != vga_default_device())
+			vgaarb_info(dev, "overriding boot device\n");
+		vga_set_default_device(pdev);
+	}
+#endif
+}
+
 static bool vga_arb_integrated_gpu(struct device *dev)
 {
 #if defined(CONFIG_ACPI)
@@ -1446,54 +1498,9 @@ static void __init vga_arb_select_default_device(void)
 	struct pci_dev *pdev, *found = NULL;
 	struct vga_device *vgadev;
 
-#if defined(CONFIG_X86) || defined(CONFIG_IA64)
-	u64 base = screen_info.lfb_base;
-	u64 size = screen_info.lfb_size;
-	u64 limit;
-	resource_size_t start, end;
-	unsigned long flags;
-	int i;
-
-	if (screen_info.capabilities & VIDEO_CAPABILITY_64BIT_BASE)
-		base |= (u64)screen_info.ext_lfb_base << 32;
-
-	limit = base + size;
-
 	list_for_each_entry(vgadev, &vga_list, list) {
-		struct device *dev = &vgadev->pdev->dev;
-		/*
-		 * Override vga_arbiter_add_pci_device()'s I/O based detection
-		 * as it may take the wrong device (e.g. on Apple system under
-		 * EFI).
-		 *
-		 * Select the device owning the boot framebuffer if there is
-		 * one.
-		 */
-
-		/* Does firmware framebuffer belong to us? */
-		for (i = 0; i < DEVICE_COUNT_RESOURCE; i++) {
-			flags = pci_resource_flags(vgadev->pdev, i);
-
-			if ((flags & IORESOURCE_MEM) == 0)
-				continue;
-
-			start = pci_resource_start(vgadev->pdev, i);
-			end  = pci_resource_end(vgadev->pdev, i);
-
-			if (!start || !end)
-				continue;
-
-			if (base < start || limit >= end)
-				continue;
-
-			if (!vga_default_device())
-				vgaarb_info(dev, "setting as boot device\n");
-			else if (vgadev->pdev != vga_default_device())
-				vgaarb_info(dev, "overriding boot device\n");
-			vga_set_default_device(vgadev->pdev);
-		}
+		vga_select_framebuffer_device(vgadev->pdev);
 	}
-#endif
 
 	if (!vga_default_device()) {
 		list_for_each_entry_reverse(vgadev, &vga_list, list) {
-- 
2.25.1

[PATCH v9 04/11] PCI/VGA: Factor out default VGA device selection

[Bjorn Helgaas]

From: Huacai Chen <chenhuacai@loongson.cn>

Default VGA device selection fails when PCI devices are enumerated after
the vga_arb_device_init() subsys_initcall.

vga_arbiter_add_pci_device() selects the first fully enabled device to
which legacy VGA resources are routed as the default VGA device.  This is
an ADD_DEVICE notifier, so it runs after every PCI device is enumerated.

vga_arb_select_default_device() may select framebuffer devices, partially
enabled GPUs, or non-legacy devices that don't have legacy VGA resources
routed to them as the default VGA device.  But this only happens once, from
the vga_arb_device_init() subsys_initcall, so it doesn't consider devices
enumerated after that:

  acpi_init
    acpi_scan_init
      acpi_pci_root_init         # PCI device enumeration (ACPI systems)

  vga_arb_device_init
    for_each_pci_device
      vga_arbiter_add_pci_device      # ADD_DEVICE notifier
        if (VGA-owner)
          vga_set_default_device      <-- set default VGA
    vga_arb_select_default_device     # only called ONCE
      for_each_vga_device
        if (framebuffer)
          vga_set_default_device      <-- set default VGA to framebuffer
      if (!vga_default_device())
        if (non-legacy, integrated GPU, etc)
          vga_set_default_device      <-- set default VGA
      if (!vga_default_device())
        vga_set_default_device        <-- set default VGA

  pcibios_init
    pcibios_scanbus              # PCI device enumeration (non-ACPI systems)
      ...
        vga_arbiter_add_pci_device    # ADD_DEVICE notification
          if (VGA-owner)
            vga_set_default_device    <-- set default VGA

Note that on non-ACPI systems, vga_arb_select_default_device() runs before
pcibios_init(), so it sees no VGA devices and can never set a framebuffer
device, a non-legacy integrated GPU, etc., as the default device.

Factor out the default VGA device selection to vga_is_boot_device(), called
from vga_arbiter_add_pci_device().

Then we can migrate the default device selection from
vga_arb_select_default_device() to the vga_arbiter_add_pci_device() path.

[bhelgaas: commit log, split to separate patch]
Link: https://lore.kernel.org/r/20211015061512.2941859-4-chenhuacai@loongson.cn
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
---
 drivers/pci/vgaarb.c | 45 ++++++++++++++++++++++++++++++++++++++------
 1 file changed, 39 insertions(+), 6 deletions(-)

diff --git a/drivers/pci/vgaarb.c b/drivers/pci/vgaarb.c
index 3f8fead49197..58e0a12e623b 100644
--- a/drivers/pci/vgaarb.c
+++ b/drivers/pci/vgaarb.c
@@ -628,6 +628,41 @@ static bool vga_arb_integrated_gpu(struct device *dev)
 #endif
 }
 
+/*
+ * Return true if vgadev is a better default VGA device than the best one
+ * we've seen so far.
+ */
+static bool vga_is_boot_device(struct vga_device *vgadev)
+{
+	struct vga_device *boot_vga = vgadev_find(vga_default_device());
+
+	/*
+	 * We select the default VGA device in this order:
+	 *   Firmware framebuffer (see vga_arb_select_default_device())
+	 *   Legacy VGA device (owns VGA_RSRC_LEGACY_MASK)
+	 *   Non-legacy integrated device (see vga_arb_select_default_device())
+	 *   Non-legacy discrete device (see vga_arb_select_default_device())
+	 *   Other device (see vga_arb_select_default_device())
+	 */
+
+	/*
+	 * A legacy VGA device has MEM and IO enabled and any bridges
+	 * leading to it have PCI_BRIDGE_CTL_VGA enabled so the legacy
+	 * resources ([mem 0xa0000-0xbffff], [io 0x3b0-0x3bb], etc) are
+	 * routed to it.
+	 *
+	 * We use the first one we find, so if we've already found one,
+	 * vgadev is no better.
+	 */
+	if (boot_vga)
+		return false;
+
+	if ((vgadev->owns & VGA_RSRC_LEGACY_MASK) == VGA_RSRC_LEGACY_MASK)
+		return true;
+
+	return false;
+}
+
 /*
  * 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
@@ -755,12 +790,10 @@ static bool vga_arbiter_add_pci_device(struct pci_dev *pdev)
 		bus = bus->parent;
 	}
 
-	/* Deal with VGA default device. Use first enabled one
-	 * by default if arch doesn't have it's own hook
-	 */
-	if (vga_default == NULL &&
-	    ((vgadev->owns & VGA_RSRC_LEGACY_MASK) == VGA_RSRC_LEGACY_MASK)) {
-		vgaarb_info(&pdev->dev, "setting as boot VGA device\n");
+	if (vga_is_boot_device(vgadev)) {
+		vgaarb_info(&pdev->dev, "setting as boot VGA device%s\n",
+			    vga_default_device() ?
+			    " (overriding previous)" : "");
 		vga_set_default_device(pdev);
 	}
 
-- 
2.25.1

[PATCH v9 05/11] PCI/VGA: Move firmware default device detection to ADD_DEVICE path

[Bjorn Helgaas]

From: Huacai Chen <chenhuacai@loongson.cn>

Previously we selected the firmware default device, i.e., one that owns the
boot framebuffer, as the default device in vga_arb_select_default_device().
This was only done in the vga_arb_device_init() subsys_initcall, so devices
enumerated later, e.g., by pcibios_init(), were not eligible.

Fix this by moving the firmware default device selection from
vga_arb_select_default_device() to vga_arbiter_add_pci_device(), which is
called after every PCI device is enumerated, either by the
vga_arb_device_init() subsys_initcall or as an ADD_DEVICE notifier.

Note that if vga_arb_select_default_device() previously found a device
owning the boot framebuffer, it unconditionally set it to be the default
VGA device, and no subsequent device could replace it.

[bhelgaas: commit log, restructure slightly]
Link: https://lore.kernel.org/r/20211015061512.2941859-7-chenhuacai@loongson.cn
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
Cc: Bruno Prémont <bonbons@linux-vserver.org>
---
 drivers/pci/vgaarb.c | 37 +++++++++++++++++--------------------
 1 file changed, 17 insertions(+), 20 deletions(-)

diff --git a/drivers/pci/vgaarb.c b/drivers/pci/vgaarb.c
index 58e0a12e623b..c3323ab4f98e 100644
--- a/drivers/pci/vgaarb.c
+++ b/drivers/pci/vgaarb.c
@@ -72,6 +72,7 @@ struct vga_device {
 	unsigned int io_norm_cnt;	/* normal IO count */
 	unsigned int mem_norm_cnt;	/* normal MEM count */
 	bool bridge_has_one_vga;
+	bool is_firmware_default;	/* device selected by firmware */
 	unsigned int (*set_decode)(struct pci_dev *pdev, bool decode);
 };
 
@@ -565,10 +566,9 @@ void vga_put(struct pci_dev *pdev, unsigned int rsrc)
 }
 EXPORT_SYMBOL(vga_put);
 
-static void __init vga_select_framebuffer_device(struct pci_dev *pdev)
+static bool vga_is_firmware_default(struct pci_dev *pdev)
 {
 #if defined(CONFIG_X86) || defined(CONFIG_IA64)
-	struct device *dev = &pdev->dev;
 	u64 base = screen_info.lfb_base;
 	u64 size = screen_info.lfb_size;
 	u64 limit;
@@ -583,15 +583,6 @@ static void __init vga_select_framebuffer_device(struct pci_dev *pdev)
 
 	limit = base + size;
 
-	/*
-	 * Override vga_arbiter_add_pci_device()'s I/O based detection
-	 * as it may take the wrong device (e.g. on Apple system under
-	 * EFI).
-	 *
-	 * Select the device owning the boot framebuffer if there is
-	 * one.
-	 */
-
 	/* Does firmware framebuffer belong to us? */
 	for (i = 0; i < DEVICE_COUNT_RESOURCE; i++) {
 		flags = pci_resource_flags(pdev, i);
@@ -608,13 +599,10 @@ static void __init vga_select_framebuffer_device(struct pci_dev *pdev)
 		if (base < start || limit >= end)
 			continue;
 
-		if (!vga_default_device())
-			vgaarb_info(dev, "setting as boot device\n");
-		else if (pdev != vga_default_device())
-			vgaarb_info(dev, "overriding boot device\n");
-		vga_set_default_device(pdev);
+		return true;
 	}
 #endif
+	return false;
 }
 
 static bool vga_arb_integrated_gpu(struct device *dev)
@@ -635,6 +623,7 @@ static bool vga_arb_integrated_gpu(struct device *dev)
 static bool vga_is_boot_device(struct vga_device *vgadev)
 {
 	struct vga_device *boot_vga = vgadev_find(vga_default_device());
+	struct pci_dev *pdev = vgadev->pdev;
 
 	/*
 	 * We select the default VGA device in this order:
@@ -645,6 +634,18 @@ static bool vga_is_boot_device(struct vga_device *vgadev)
 	 *   Other device (see vga_arb_select_default_device())
 	 */
 
+	/*
+	 * We always prefer a firmware default device, so if we've already
+	 * found one, there's no need to consider vgadev.
+	 */
+	if (boot_vga && boot_vga->is_firmware_default)
+		return false;
+
+	if (vga_is_firmware_default(pdev)) {
+		vgadev->is_firmware_default = true;
+		return true;
+	}
+
 	/*
 	 * A legacy VGA device has MEM and IO enabled and any bridges
 	 * leading to it have PCI_BRIDGE_CTL_VGA enabled so the legacy
@@ -1531,10 +1532,6 @@ static void __init vga_arb_select_default_device(void)
 	struct pci_dev *pdev, *found = NULL;
 	struct vga_device *vgadev;
 
-	list_for_each_entry(vgadev, &vga_list, list) {
-		vga_select_framebuffer_device(vgadev->pdev);
-	}
-
 	if (!vga_default_device()) {
 		list_for_each_entry_reverse(vgadev, &vga_list, list) {
 			struct device *dev = &vgadev->pdev->dev;
-- 
2.25.1

[PATCH v9 06/11] PCI/VGA: Move non-legacy VGA detection to ADD_DEVICE path

[Bjorn Helgaas]

From: Huacai Chen <chenhuacai@loongson.cn>

a37c0f48950b ("vgaarb: Select a default VGA device even if there's no
legacy VGA") extended the vga_arb_device_init() subsys_initcall so it could
select a non-legacy VGA device as the default.

That failed to consider that PCI devices may be enumerated after
vga_arb_device_init(), e.g., hot-added devices or non-ACPI systems that do
PCI enumeration in pcibios_init().  Devices found then could never be
selected as the default.

One system where this is a problem is the MIPS-based Loongson where an
ASpeed AST2500 VGA device is behind a bridge that doesn't implement the VGA
Enable bit, so legacy resources are not routed to the VGA device. [1]

Fix this by moving the non-legacy VGA device selection from
vga_arb_select_default_device() to vga_arbiter_add_pci_device(), which is
called after every PCI device is enumerated, either by the
vga_arb_device_init() subsys_initcall or as an ADD_DEVICE notifier.

[1] https://lore.kernel.org/r/20210514080025.1828197-6-chenhuacai@loongson.cn

[bhelgaas: commit log, restructure]
Link: https://lore.kernel.org/r/20211015061512.2941859-5-chenhuacai@loongson.cn
Link: https://lore.kernel.org/r/20211015061512.2941859-7-chenhuacai@loongson.cn
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
Cc: Daniel Axtens <dja@axtens.net>
Cc: Zhou Wang <wangzhou1@hisilicon.com>
---
 drivers/pci/vgaarb.c | 54 ++++++++++++++++++++++++++------------------
 1 file changed, 32 insertions(+), 22 deletions(-)

diff --git a/drivers/pci/vgaarb.c b/drivers/pci/vgaarb.c
index c3323ab4f98e..e36ccbfdbd89 100644
--- a/drivers/pci/vgaarb.c
+++ b/drivers/pci/vgaarb.c
@@ -624,6 +624,7 @@ static bool vga_is_boot_device(struct vga_device *vgadev)
 {
 	struct vga_device *boot_vga = vgadev_find(vga_default_device());
 	struct pci_dev *pdev = vgadev->pdev;
+	u16 cmd, boot_cmd;
 
 	/*
 	 * We select the default VGA device in this order:
@@ -661,6 +662,37 @@ static bool vga_is_boot_device(struct vga_device *vgadev)
 	if ((vgadev->owns & VGA_RSRC_LEGACY_MASK) == VGA_RSRC_LEGACY_MASK)
 		return true;
 
+	/*
+	 * If we haven't found a legacy VGA device, accept a non-legacy
+	 * device.  It may have either IO or MEM enabled, and bridges may
+	 * not have PCI_BRIDGE_CTL_VGA enabled, so it may not be able to
+	 * use legacy VGA resources.  Prefer an integrated GPU over others.
+	 */
+	pci_read_config_word(pdev, PCI_COMMAND, &cmd);
+	if (cmd & (PCI_COMMAND_IO | PCI_COMMAND_MEMORY)) {
+
+		/*
+		 * An integrated GPU overrides a previous non-legacy
+		 * device.  We expect only a single integrated GPU, but if
+		 * there are more, we use the *last* because that was the
+		 * previous behavior.
+		 */
+		if (vga_arb_integrated_gpu(&pdev->dev))
+			return true;
+
+		/*
+		 * We prefer the first non-legacy discrete device we find.
+		 * If we already found one, vgadev is no better.
+		 */
+		if (boot_vga) {
+			pci_read_config_word(boot_vga->pdev, PCI_COMMAND,
+					     &boot_cmd);
+			if (boot_cmd & (PCI_COMMAND_IO | PCI_COMMAND_MEMORY))
+				return false;
+		}
+		return true;
+	}
+
 	return false;
 }
 
@@ -1529,30 +1561,8 @@ static struct miscdevice vga_arb_device = {
 
 static void __init vga_arb_select_default_device(void)
 {
-	struct pci_dev *pdev, *found = NULL;
 	struct vga_device *vgadev;
 
-	if (!vga_default_device()) {
-		list_for_each_entry_reverse(vgadev, &vga_list, list) {
-			struct device *dev = &vgadev->pdev->dev;
-			u16 cmd;
-
-			pdev = vgadev->pdev;
-			pci_read_config_word(pdev, PCI_COMMAND, &cmd);
-			if (cmd & (PCI_COMMAND_IO | PCI_COMMAND_MEMORY)) {
-				found = pdev;
-				if (vga_arb_integrated_gpu(dev))
-					break;
-			}
-		}
-	}
-
-	if (found) {
-		vgaarb_info(&found->dev, "setting as boot device (VGA legacy resources not available)\n");
-		vga_set_default_device(found);
-		return;
-	}
-
 	if (!vga_default_device()) {
 		vgadev = list_first_entry_or_null(&vga_list,
 						  struct vga_device, list);
-- 
2.25.1

[PATCH v9 07/11] PCI/VGA: Move disabled VGA device detection to ADD_DEVICE path

[Bjorn Helgaas]

From: Huacai Chen <chenhuacai@loongson.cn>

a37c0f48950b ("vgaarb: Select a default VGA device even if there's no
legacy VGA") extended the vga_arb_device_init() subsys_initcall so that if
there are no other eligible devices, it could select a disabled VGA device
as the default.

Move this detection from vga_arb_select_default_device() to
vga_arbiter_add_pci_device() so every device, even those hot-added or
enumerated after vga_arb_device_init() is eligible for selection as the
default VGA device.

[bhelgaas: commit log, restructure]
Link: https://lore.kernel.org/r/20211015061512.2941859-5-chenhuacai@loongson.cn
Signed-off-by: Huacai Chen <chenhuacai@kernel.org>
Cc: Daniel Axtens <dja@axtens.net>
Cc: Zhou Wang <wangzhou1@hisilicon.com>
---
 drivers/pci/vgaarb.c | 27 +++++++++------------------
 1 file changed, 9 insertions(+), 18 deletions(-)

diff --git a/drivers/pci/vgaarb.c b/drivers/pci/vgaarb.c
index e36ccbfdbd89..e8d5efd85ba6 100644
--- a/drivers/pci/vgaarb.c
+++ b/drivers/pci/vgaarb.c
@@ -656,7 +656,8 @@ static bool vga_is_boot_device(struct vga_device *vgadev)
 	 * We use the first one we find, so if we've already found one,
 	 * vgadev is no better.
 	 */
-	if (boot_vga)
+	if (boot_vga &&
+	    (boot_vga->owns & VGA_RSRC_LEGACY_MASK) == VGA_RSRC_LEGACY_MASK)
 		return false;
 
 	if ((vgadev->owns & VGA_RSRC_LEGACY_MASK) == VGA_RSRC_LEGACY_MASK)
@@ -693,6 +694,13 @@ static bool vga_is_boot_device(struct vga_device *vgadev)
 		return true;
 	}
 
+	/*
+	 * 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)
+		return true;
+
 	return false;
 }
 
@@ -1559,21 +1567,6 @@ static struct miscdevice vga_arb_device = {
 	MISC_DYNAMIC_MINOR, "vga_arbiter", &vga_arb_device_fops
 };
 
-static void __init vga_arb_select_default_device(void)
-{
-	struct vga_device *vgadev;
-
-	if (!vga_default_device()) {
-		vgadev = list_first_entry_or_null(&vga_list,
-						  struct vga_device, list);
-		if (vgadev) {
-			struct device *dev = &vgadev->pdev->dev;
-			vgaarb_info(dev, "setting as boot device (VGA legacy resources not available)\n");
-			vga_set_default_device(vgadev->pdev);
-		}
-	}
-}
-
 static int __init vga_arb_device_init(void)
 {
 	int rc;
@@ -1603,8 +1596,6 @@ static int __init vga_arb_device_init(void)
 			vgaarb_info(dev, "no bridge control possible\n");
 	}
 
-	vga_arb_select_default_device();
-
 	pr_info("loaded\n");
 	return rc;
 }
-- 
2.25.1

[PATCH v9 08/11] PCI/VGA: Remove empty vga_arb_device_card_gone()

[Bjorn Helgaas]

From: Bjorn Helgaas <bhelgaas@google.com>

vga_arb_device_card_gone() has always been empty.  Remove it.

Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
---
 drivers/pci/vgaarb.c | 16 +---------------
 1 file changed, 1 insertion(+), 15 deletions(-)

diff --git a/drivers/pci/vgaarb.c b/drivers/pci/vgaarb.c
index e8d5efd85ba6..582f0054b71a 100644
--- a/drivers/pci/vgaarb.c
+++ b/drivers/pci/vgaarb.c
@@ -123,8 +123,6 @@ static int vga_str_to_iostate(char *buf, int str_size, int *io_state)
 /* this is only used a cookie - it should not be dereferenced */
 static struct pci_dev *vga_default;
 
-static void vga_arb_device_card_gone(struct pci_dev *pdev);
-
 /* Find somebody in our list */
 static struct vga_device *vgadev_find(struct pci_dev *pdev)
 {
@@ -878,10 +876,6 @@ static bool vga_arbiter_del_pci_device(struct pci_dev *pdev)
 	/* Remove entry from list */
 	list_del(&vgadev->list);
 	vga_count--;
-	/* Notify userland driver that the device is gone so it discards
-	 * it's copies of the pci_dev pointer
-	 */
-	vga_arb_device_card_gone(pdev);
 
 	/* Wake up all possible waiters */
 	wake_up_all(&vga_wait_queue);
@@ -1131,9 +1125,7 @@ static ssize_t vga_arb_read(struct file *file, char __user *buf,
 	if (lbuf == NULL)
 		return -ENOMEM;
 
-	/* Shields against vga_arb_device_card_gone (pci_dev going
-	 * away), and allows access to vga list
-	 */
+	/* Protects vga_list */
 	spin_lock_irqsave(&vga_lock, flags);
 
 	/* If we are targeting the default, use it */
@@ -1150,8 +1142,6 @@ static ssize_t vga_arb_read(struct file *file, char __user *buf,
 		/* Wow, it's not in the list, that shouldn't happen,
 		 * let's fix us up and return invalid card
 		 */
-		if (pdev == priv->target)
-			vga_arb_device_card_gone(pdev);
 		spin_unlock_irqrestore(&vga_lock, flags);
 		len = sprintf(lbuf, "invalid");
 		goto done;
@@ -1495,10 +1485,6 @@ static int vga_arb_release(struct inode *inode, struct file *file)
 	return 0;
 }
 
-static void vga_arb_device_card_gone(struct pci_dev *pdev)
-{
-}
-
 /*
  * callback any registered clients to let them know we have a
  * change in VGA cards
-- 
2.25.1

[PATCH v9 09/11] PCI/VGA: Log bridge control messages when adding devices

[Bjorn Helgaas]

From: Huacai Chen <chenhuacai@loongson.cn>

Previously vga_arb_device_init() iterated through all VGA devices and
indicated whether legacy VGA routing to each could be controlled by an
upstream bridge.

But we determine that information in vga_arbiter_add_pci_device(), which we
call for every device, so we can log it there without iterating through the
VGA devices again.

Note that we call vga_arbiter_check_bridge_sharing() before adding the
device to vga_list, so we have to handle the very first device separately.

Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
---
 drivers/pci/vgaarb.c | 19 ++++++++-----------
 1 file changed, 8 insertions(+), 11 deletions(-)

diff --git a/drivers/pci/vgaarb.c b/drivers/pci/vgaarb.c
index 582f0054b71a..7b1bfdea9d10 100644
--- a/drivers/pci/vgaarb.c
+++ b/drivers/pci/vgaarb.c
@@ -719,8 +719,10 @@ static void vga_arbiter_check_bridge_sharing(struct vga_device *vgadev)
 
 	vgadev->bridge_has_one_vga = true;
 
-	if (list_empty(&vga_list))
+	if (list_empty(&vga_list)) {
+		vgaarb_info(&vgadev->pdev->dev, "bridge control possible\n");
 		return;
+	}
 
 	/* okay iterate the new devices bridge hierarachy */
 	new_bus = vgadev->pdev->bus;
@@ -759,6 +761,11 @@ static void vga_arbiter_check_bridge_sharing(struct vga_device *vgadev)
 		}
 		new_bus = new_bus->parent;
 	}
+
+	if (vgadev->bridge_has_one_vga)
+		vgaarb_info(&vgadev->pdev->dev, "bridge control possible\n");
+	else
+		vgaarb_info(&vgadev->pdev->dev, "no bridge control possible\n");
 }
 
 /*
@@ -1557,7 +1564,6 @@ 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)
@@ -1573,15 +1579,6 @@ static int __init vga_arb_device_init(void)
 			       PCI_ANY_ID, pdev)) != NULL)
 		vga_arbiter_add_pci_device(pdev);
 
-	list_for_each_entry(vgadev, &vga_list, list) {
-		struct device *dev = &vgadev->pdev->dev;
-
-		if (vgadev->bridge_has_one_vga)
-			vgaarb_info(dev, "bridge control possible\n");
-		else
-			vgaarb_info(dev, "no bridge control possible\n");
-	}
-
 	pr_info("loaded\n");
 	return rc;
 }
-- 
2.25.1

[PATCH v9 10/11] PCI/VGA: Use unsigned format string to print lock counts

[Bjorn Helgaas]

From: Bjorn Helgaas <bhelgaas@google.com>

In struct vga_device, io_lock_cnt and mem_lock_cnt are unsigned, but we
previously printed them with "%d", the signed decimal format.  Print them
with the unsigned format "%u" instead.

Signed-off-by: Bjorn Helgaas <bhelgaas@google.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 7b1bfdea9d10..d6e77c6a9a1a 100644
--- a/drivers/pci/vgaarb.c
+++ b/drivers/pci/vgaarb.c
@@ -1156,7 +1156,7 @@ static ssize_t vga_arb_read(struct file *file, char __user *buf,
 
 	/* Fill the buffer with infos */
 	len = snprintf(lbuf, 1024,
-		       "count:%d,PCI:%s,decodes=%s,owns=%s,locks=%s(%d:%d)\n",
+		       "count:%d,PCI:%s,decodes=%s,owns=%s,locks=%s(%u:%u)\n",
 		       vga_decode_count, pci_name(pdev),
 		       vga_iostate_to_str(vgadev->decodes),
 		       vga_iostate_to_str(vgadev->owns),
-- 
2.25.1

[PATCH v9 11/11] PCI/VGA: Replace full MIT license text with SPDX identifier

[Bjorn Helgaas]

From: Bjorn Helgaas <bhelgaas@google.com>

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.

Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
---
 drivers/pci/vgaarb.c | 23 +----------------------
 1 file changed, 1 insertion(+), 22 deletions(-)

diff --git a/drivers/pci/vgaarb.c b/drivers/pci/vgaarb.c
index d6e77c6a9a1a..f80b6ec88dc3 100644
--- a/drivers/pci/vgaarb.c
+++ b/drivers/pci/vgaarb.c
@@ -1,32 +1,11 @@
+// SPDX-License-Identifier: MIT
 /*
  * vgaarb.c: Implements the VGA arbitration. For details refer to
  * Documentation/gpu/vgaarbiter.rst
  *
- *
  * (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>
- *
- * 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.
- *
  */
 
 #define pr_fmt(fmt) "vgaarb: " fmt
-- 
2.25.1

Re: [PATCH v9 00/11] vgaarb: Rework default VGA device selection

[Bjorn Helgaas]

On Thu, Feb 24, 2022 at 04:47:42PM -0600, Bjorn Helgaas wrote:
> From: Bjorn Helgaas <bhelgaas@google.com>
> 
> Current default VGA device selection fails in some cases because part of it
> is done in the vga_arb_device_init() subsys_initcall, and some arches
> enumerate PCI devices in pcibios_init(), which runs *after* that.
> 
> The big change from the v8 posting is that this moves vgaarb.c from
> drivers/gpu/vga to drivers/pci because it really has nothing to do with
> GPUs or DRM.

I provisionally applied this to pci/vga and put it into -next just
to get a little runtime on it.

But I'd prefer not to unilaterally yank this out of drivers/gpu
without a consensus from the GPU folks that this is the right thing to
do.

Any thoughts?  If it seems OK to you, I think patch 1/11 (the move
itself) is all you would need to look at, although of course I would
still be grateful for any review and feedback on the rest.

After it's in drivers/pci, all the blame for any issues would come my
way.

Bjorn

Re: [PATCH v9 00/11] vgaarb: Rework default VGA device selection

[Bjorn Helgaas]

On Fri, Feb 25, 2022 at 04:15:23PM -0600, Bjorn Helgaas wrote:
> On Thu, Feb 24, 2022 at 04:47:42PM -0600, Bjorn Helgaas wrote:
> > From: Bjorn Helgaas <bhelgaas@google.com>
> > 
> > Current default VGA device selection fails in some cases because part of it
> > is done in the vga_arb_device_init() subsys_initcall, and some arches
> > enumerate PCI devices in pcibios_init(), which runs *after* that.
> > 
> > The big change from the v8 posting is that this moves vgaarb.c from
> > drivers/gpu/vga to drivers/pci because it really has nothing to do with
> > GPUs or DRM.
> 
> I provisionally applied this to pci/vga and put it into -next just
> to get a little runtime on it.
> 
> But I'd prefer not to unilaterally yank this out of drivers/gpu
> without a consensus from the GPU folks that this is the right thing to
> do.
> 
> Any thoughts?  If it seems OK to you, I think patch 1/11 (the move
> itself) is all you would need to look at, although of course I would
> still be grateful for any review and feedback on the rest.
> 
> After it's in drivers/pci, all the blame for any issues would come my
> way.

Ping?  This has been in -next since the Feb 28 tree, and I plan to
ask Linus to include it during the v5.18 merge window (which will
probably open Mar 13) unless somebody objects.

Bjorn

Re: [PATCH v9 00/11] vgaarb: Rework default VGA device selection

[Huacai Chen]

I have no objection :)

Huacai

On Thu, Mar 10, 2022 at 12:29 AM Bjorn Helgaas <helgaas@kernel.org> wrote:
>
> On Fri, Feb 25, 2022 at 04:15:23PM -0600, Bjorn Helgaas wrote:
> > On Thu, Feb 24, 2022 at 04:47:42PM -0600, Bjorn Helgaas wrote:
> > > From: Bjorn Helgaas <bhelgaas@google.com>
> > >
> > > Current default VGA device selection fails in some cases because part of it
> > > is done in the vga_arb_device_init() subsys_initcall, and some arches
> > > enumerate PCI devices in pcibios_init(), which runs *after* that.
> > >
> > > The big change from the v8 posting is that this moves vgaarb.c from
> > > drivers/gpu/vga to drivers/pci because it really has nothing to do with
> > > GPUs or DRM.
> >
> > I provisionally applied this to pci/vga and put it into -next just
> > to get a little runtime on it.
> >
> > But I'd prefer not to unilaterally yank this out of drivers/gpu
> > without a consensus from the GPU folks that this is the right thing to
> > do.
> >
> > Any thoughts?  If it seems OK to you, I think patch 1/11 (the move
> > itself) is all you would need to look at, although of course I would
> > still be grateful for any review and feedback on the rest.
> >
> > After it's in drivers/pci, all the blame for any issues would come my
> > way.
>
> Ping?  This has been in -next since the Feb 28 tree, and I plan to
> ask Linus to include it during the v5.18 merge window (which will
> probably open Mar 13) unless somebody objects.
>
> Bjorn