Currently, vga_arb_device_init() selects the first probed VGA device
with VGA legacy resources enabled as the default device. However, some
BMC-based VGA cards (e.g., AST2500 and HiSilicon D05) don't enable VGA
legacy resources because their built-in upstream bridges don't support
PCI_BRIDGE_CTL_VGA. This makes "no default VGA card" and breaks X.org
auto-detection.
Commit a37c0f48950b56f6ef2e ("vgaarb: Select a default VGA device even
if there's no legacy VGA") try to solve this problem but fails on some
platforms, because it relies on the initcall order:
We should call vga_arb_device_init() after PCI enumeration, otherwise it
may fail to select the default VGA device. Since vga_arb_device_init()
and PCI enumeration function (i.e., pcibios_init() or acpi_init()) are
both wrapped by subsys_initcall(), their sequence is not assured. So, it
is possible to use subsys_initcall_sync() instead of subsys_initcall()
to wrap vga_arb_device_init().
However, the above approach still has drawbacks, it cannot handle the
cases that a VGA card is hot-plugged, or the gpu driver is compiled as a
module.
So, as suggested by Bjorn Helgaas, this patch rework the selection:
1, Remove direct vga_arb_select_default_device() calls in vga_arb_
device_init().
2, Rename vga_arb_select_default_device() to vga_arb_update_default_
device(), which selects the first probed VGA device as the default
(whether legacy resources enabled or not), and update the default
device if a better one is found (device with legacy resources enabled
is better, device owns the firmware framebuffer is even better).
3, Every time a new VGA device is probed, vga_arbiter_add_pci_device()
is called, and vga_arb_update_default_device() is also called. So the
hotplug case and the module case can also be handled.
Signed-off-by: Huacai Chen <chenhua...@loongson.cn>
---
drivers/gpu/vga/vgaarb.c | 219 +++++++++++++++++----------------------
1 file changed, 97 insertions(+), 122 deletions(-)
diff --git a/drivers/gpu/vga/vgaarb.c b/drivers/gpu/vga/vgaarb.c
index 949fde433ea2..07770aae3aaf 100644
--- a/drivers/gpu/vga/vgaarb.c
+++ b/drivers/gpu/vga/vgaarb.c
@@ -586,6 +586,97 @@ void vga_put(struct pci_dev *pdev, unsigned int rsrc)
}
EXPORT_SYMBOL(vga_put);
+#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 vga_arb_update_default_device(struct vga_device *vgadev)
+{
+ struct pci_dev *pdev = vgadev->pdev;
+ struct device *dev = &pdev->dev;
+ struct vga_device *vgadev_default;
+#if defined(CONFIG_X86) || defined(CONFIG_IA64)
+ int i;
+ unsigned long flags;
+ u64 base = screen_info.lfb_base;
+ u64 size = screen_info.lfb_size;
+ u64 limit;
+ resource_size_t start, end;
+#endif
+
+ /* Deal with VGA default device. Use first enabled one
+ * by default if arch doesn't have it's own hook
+ */
+ if (!vga_default_device()) {
+ if ((vgadev->owns & VGA_RSRC_LEGACY_MASK) ==
VGA_RSRC_LEGACY_MASK)
+ vgaarb_info(dev, "setting as boot VGA device\n");
+ else
+ vgaarb_info(dev, "setting as boot device (VGA legacy
resources not available)\n");
+ vga_set_default_device(pdev);
+ }
+
+ vgadev_default = vgadev_find(vga_default);
+
+ /* Overridden by a better device */
+ if (vgadev_default && ((vgadev_default->owns & VGA_RSRC_LEGACY_MASK) ==
0)
+ && ((vgadev->owns & VGA_RSRC_LEGACY_MASK) ==
VGA_RSRC_LEGACY_MASK)) {
+ vgaarb_info(dev, "overriding boot VGA device\n");
+ vga_set_default_device(pdev);
+ }
+
+ if (vga_arb_integrated_gpu(dev)) {
+ vgaarb_info(dev, "overriding boot VGA device\n");
+ vga_set_default_device(pdev);
+ }
+
+#if defined(CONFIG_X86) || defined(CONFIG_IA64)
+ 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(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 (vgadev->pdev != vga_default_device())
+ vgaarb_info(dev, "overriding boot device\n");
+ vga_set_default_device(vgadev->pdev);
+ }
+#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
@@ -643,6 +734,11 @@ static void vga_arbiter_check_bridge_sharing(struct
vga_device *vgadev)
}
new_bus = new_bus->parent;
}
+
+ if (vgadev->bridge_has_one_vga == true)
+ vgaarb_info(&vgadev->pdev->dev, "bridge control possible\n");
+ else
+ vgaarb_info(&vgadev->pdev->dev, "no bridge control possible\n");
}
/*
@@ -713,15 +809,7 @@ 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");
- vga_set_default_device(pdev);
- }
-
+ vga_arb_update_default_device(vgadev);
vga_arbiter_check_bridge_sharing(vgadev);
/* Add to the list */
@@ -1451,111 +1539,10 @@ 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;
- 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);
- }
- }
-#endif
-
- 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);
- 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;
struct pci_dev *pdev;
- struct vga_device *vgadev;
rc = misc_register(&vga_arb_device);
if (rc < 0)
@@ -1571,18 +1558,6 @@ 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");
- }
-
- vga_arb_select_default_device();
-
- pr_info("loaded\n");
return rc;
}
subsys_initcall(vga_arb_device_init);
--
2.27.0
