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 chenhuacai@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);