[PATCH v4 2/4] PCI/VGA: Deal only with VGA class devices

From: Sui Jingfeng
Date: Fri Jun 09 2023 - 06:36:46 EST


Deal only with the VGA devcie(pdev->class == 0x0300), so replace the
pci_get_subsys() function with pci_get_class(). Filter the non-PCI display
device(pdev->class != 0x0300) out. There no need to process the non-display
PCI device.

Signed-off-by: Sui Jingfeng <suijingfeng@xxxxxxxxxxx>
---
drivers/pci/vgaarb.c | 22 ++++++++++++----------
1 file changed, 12 insertions(+), 10 deletions(-)

diff --git a/drivers/pci/vgaarb.c b/drivers/pci/vgaarb.c
index c1bc6c983932..22a505e877dc 100644
--- a/drivers/pci/vgaarb.c
+++ b/drivers/pci/vgaarb.c
@@ -754,10 +754,6 @@ static bool vga_arbiter_add_pci_device(struct pci_dev *pdev)
struct pci_dev *bridge;
u16 cmd;

- /* Only deal with VGA class devices */
- if ((pdev->class >> 8) != PCI_CLASS_DISPLAY_VGA)
- return false;
-
/* Allocate structure */
vgadev = kzalloc(sizeof(struct vga_device), GFP_KERNEL);
if (vgadev == NULL) {
@@ -1500,7 +1496,9 @@ static int pci_notify(struct notifier_block *nb, unsigned long action,
struct pci_dev *pdev = to_pci_dev(dev);
bool notify = false;

- vgaarb_dbg(dev, "%s\n", __func__);
+ /* Only deal with VGA class devices */
+ if (pdev->class != PCI_CLASS_DISPLAY_VGA << 8)
+ return 0;

/* For now we're only intereted in devices added and removed. I didn't
* test this thing here, so someone needs to double check for the
@@ -1510,6 +1508,8 @@ static int pci_notify(struct notifier_block *nb, unsigned long action,
else if (action == BUS_NOTIFY_DEL_DEVICE)
notify = vga_arbiter_del_pci_device(pdev);

+ vgaarb_dbg(dev, "%s: action = %lu\n", __func__, action);
+
if (notify)
vga_arbiter_notify_clients();
return 0;
@@ -1534,8 +1534,8 @@ static struct miscdevice vga_arb_device = {

static int __init vga_arb_device_init(void)
{
+ struct pci_dev *pdev = NULL;
int rc;
- struct pci_dev *pdev;

rc = misc_register(&vga_arb_device);
if (rc < 0)
@@ -1545,11 +1545,13 @@ static int __init vga_arb_device_init(void)

/* 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)
+ while (1) {
+ pdev = pci_get_class(PCI_CLASS_DISPLAY_VGA << 8, pdev);
+ if (!pdev)
+ break;
+
vga_arbiter_add_pci_device(pdev);
+ }

pr_info("loaded\n");
return rc;
--
2.25.1