PCI/VGA: Log bridge control messages when adding devices

Previously vga_arb_device_init() iterated through all VGA devices and
indicated whether legacy VGA routing to each could be controlled by an
upstream bridge.

But we determine that information in vga_arbiter_add_pci_device(), which we
call for every device, so we can log it there without iterating through the
VGA devices again.

Note that we call vga_arbiter_check_bridge_sharing() before adding the
device to vga_list, so we have to handle the very first device separately.

Link: https://lore.kernel.org/r/20220224224753.297579-10-helgaas@kernel.org
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>

diff --git a/drivers/pci/vgaarb.c b/drivers/pci/vgaarb.c
index 582f005..7b1bfde 100644 (file)
--- a/drivers/pci/vgaarb.c
+++ b/drivers/pci/vgaarb.c
@@ -719,8 +719,10 @@ static void vga_arbiter_check_bridge_sharing(struct vga_device *vgadev)
 
        vgadev->bridge_has_one_vga = true;
 
-       if (list_empty(&vga_list))
+       if (list_empty(&vga_list)) {
+               vgaarb_info(&vgadev->pdev->dev, "bridge control possible\n");
                return;
+       }
 
        /* okay iterate the new devices bridge hierarachy */
        new_bus = vgadev->pdev->bus;
@@ -759,6 +761,11 @@ static void vga_arbiter_check_bridge_sharing(struct vga_device *vgadev)
                }
                new_bus = new_bus->parent;
        }
+
+       if (vgadev->bridge_has_one_vga)
+               vgaarb_info(&vgadev->pdev->dev, "bridge control possible\n");
+       else
+               vgaarb_info(&vgadev->pdev->dev, "no bridge control possible\n");
 }
 
 /*
@@ -1557,7 +1564,6 @@ 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)
@@ -1573,15 +1579,6 @@ 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");
-       }
-
        pr_info("loaded\n");
        return rc;
 }