PCI/VGA: Move disabled VGA device detection to ADD_DEVICE path

a37c0f48950b ("vgaarb: Select a default VGA device even if there's no
legacy VGA") extended the vga_arb_device_init() subsys_initcall so that if
there are no other eligible devices, it could select a disabled VGA device
as the default.

Move this detection from vga_arb_select_default_device() to
vga_arbiter_add_pci_device() so every device, even those hot-added or
enumerated after vga_arb_device_init() is eligible for selection as the
default VGA device.

[bhelgaas: commit log, restructure]
Link: https://lore.kernel.org/r/20211015061512.2941859-5-chenhuacai@loongson.cn
Link: https://lore.kernel.org/r/20220224224753.297579-8-helgaas@kernel.org
Signed-off-by: Huacai Chen <chenhuacai@kernel.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Cc: Daniel Axtens <dja@axtens.net>
Cc: Zhou Wang <wangzhou1@hisilicon.com>

diff --git a/drivers/pci/vgaarb.c b/drivers/pci/vgaarb.c
index e36ccbf..e8d5efd 100644 (file)
--- a/drivers/pci/vgaarb.c
+++ b/drivers/pci/vgaarb.c
@@ -656,7 +656,8 @@ static bool vga_is_boot_device(struct vga_device *vgadev)
         * We use the first one we find, so if we've already found one,
         * vgadev is no better.
         */
-       if (boot_vga)
+       if (boot_vga &&
+           (boot_vga->owns & VGA_RSRC_LEGACY_MASK) == VGA_RSRC_LEGACY_MASK)
                return false;
 
        if ((vgadev->owns & VGA_RSRC_LEGACY_MASK) == VGA_RSRC_LEGACY_MASK)
@@ -693,6 +694,13 @@ static bool vga_is_boot_device(struct vga_device *vgadev)
                return true;
        }
 
+       /*
+        * vgadev has neither IO nor MEM enabled.  If we haven't found any
+        * other VGA devices, it is the best candidate so far.
+        */
+       if (!boot_vga)
+               return true;
+
        return false;
 }
 
@@ -1559,21 +1567,6 @@ 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 vga_device *vgadev;
-
-       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;
@@ -1603,8 +1596,6 @@ static int __init vga_arb_device_init(void)
                        vgaarb_info(dev, "no bridge control possible\n");
        }
 
-       vga_arb_select_default_device();
-
        pr_info("loaded\n");
        return rc;
 }