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);
--
2.27.0
