Current default VGA device selection fails in some cases:
- On BMC system, the AST2500 bridge [1a03:1150] does not implement PCI_BRIDGE_CTL_VGA [1]. 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().
So I made vga_arb_update_default_device() to replace the current vga_ arb_select_default_device(), which will be call from vga_arbiter_add_ pci_device(), set the default device even if it does not own the VGA resources because an upstream bridge doesn't implement PCI_BRIDGE_CTL_ VGA. And the default VGA device is updated if a better one is found (device with legacy resources enabled is better, device owns the firmware framebuffer is even better). --- drivers/pci/vgaarb.c | 158 ++++++++++++++++++------------------------- 1 file changed, 66 insertions(+), 92 deletions(-)
diff --git a/drivers/pci/vgaarb.c b/drivers/pci/vgaarb.c index dd07b1c3205f..0b059a2fc749 100644 --- a/drivers/pci/vgaarb.c +++ b/drivers/pci/vgaarb.c @@ -580,16 +580,79 @@ static bool vga_arb_integrated_gpu(struct device *dev) 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
/* * If we don't have a default VGA device yet, and this device owns * the legacy VGA resources, make it the default. */ - if (!vga_default_device() && - ((vgadev->owns & VGA_RSRC_LEGACY_MASK) == VGA_RSRC_LEGACY_MASK)) { - vgaarb_info(&pdev->dev, "setting as boot VGA device\n"); + 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 }
/* @@ -1444,92 +1507,6 @@ 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 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; @@ -1549,9 +1526,6 @@ static int __init vga_arb_device_init(void) PCI_ANY_ID, pdev)) != NULL) vga_arbiter_add_pci_device(pdev);
- vga_arb_select_default_device(); - - pr_info("loaded\n"); return rc; } subsys_initcall(vga_arb_device_init);