vgaarb: Factor out EFI and fallback default device selection

The default VGA device is normally set in vga_arbiter_add_pci_device() when
we call it for the first enabled device that can be accessed with the
legacy VGA resources ([mem 0xa0000-0xbffff], etc.)

That default device can be overridden by an EFI device that owns the boot
framebuffer.  As a fallback, we can also select a VGA device that can't be
accessed via legacy VGA resources, or a VGA device that isn't even enabled.

Factor out this EFI and fallback selection from vga_arb_device_init() into
a separate vga_arb_select_default_device() function.  This doesn't change
any behavior, but it untangles the "bridge control possible" checking and
messages from the default device selection.

Tested-by: Zhou Wang <wangzhou1@hisilicon.com>  # D05 Hisi Hip07, Hip08
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Reviewed-by: Daniel Axtens <dja@axtens.net>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20171013034729.14630.30419.stgit@bhelgaas-glaptop.roam.corp.google.com

diff --git a/drivers/gpu/vga/vgaarb.c b/drivers/gpu/vga/vgaarb.c
index 8035e38d5110ecc784b4e99c4944c081a3637460..d35d6d271f3f16d85918e137f969520fa052acd3 100644 (file)
--- a/drivers/gpu/vga/vgaarb.c
+++ b/drivers/gpu/vga/vgaarb.c
@@ -1402,29 +1402,14 @@ static struct miscdevice vga_arb_device = {
        MISC_DYNAMIC_MINOR, "vga_arbiter", &vga_arb_device_fops
 };
 
-static int __init vga_arb_device_init(void)
+static void __init vga_arb_select_default_device(void)
 {
-       int rc;
        struct pci_dev *pdev;
        struct vga_device *vgadev;
 
-       rc = misc_register(&vga_arb_device);
-       if (rc < 0)
-               pr_err("error %d registering device\n", rc);
-
-       bus_register_notifier(&pci_bus_type, &pci_notifier);
-
-       /* We add all pci devices satisfying vga class in the arbiter by
-        * default */
-       pdev = NULL;
-       while ((pdev =
-               pci_get_subsys(PCI_ANY_ID, PCI_ANY_ID, PCI_ANY_ID,
-                              PCI_ANY_ID, pdev)) != NULL)
-               vga_arbiter_add_pci_device(pdev);
-
+#if defined(CONFIG_X86) || defined(CONFIG_IA64)
        list_for_each_entry(vgadev, &vga_list, list) {
                struct device *dev = &vgadev->pdev->dev;
-#if defined(CONFIG_X86) || defined(CONFIG_IA64)
                /*
                 * Override vga_arbiter_add_pci_device()'s I/O based detection
                 * as it may take the wrong device (e.g. on Apple system under
@@ -1461,12 +1446,8 @@ static int __init vga_arb_device_init(void)
                                vgaarb_info(dev, "overriding boot device\n");
                        vga_set_default_device(vgadev->pdev);
                }
-#endif
-               if (vgadev->bridge_has_one_vga)
-                       vgaarb_info(dev, "bridge control possible\n");
-               else
-                       vgaarb_info(dev, "no bridge control possible\n");
        }
+#endif
 
        if (!vga_default_device()) {
                list_for_each_entry(vgadev, &vga_list, list) {
@@ -1492,6 +1473,38 @@ static int __init vga_arb_device_init(void)
                        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)
+               pr_err("error %d registering device\n", rc);
+
+       bus_register_notifier(&pci_bus_type, &pci_notifier);
+
+       /* We add all PCI devices satisfying VGA class in the arbiter by
+        * default */
+       pdev = NULL;
+       while ((pdev =
+               pci_get_subsys(PCI_ANY_ID, PCI_ANY_ID, PCI_ANY_ID,
+                              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;