linux-kernel - [-next 2/5] PCI/VGA: Deal with VGA devices

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Message-Id: <20230830111532.444535-3-sui.jingfeng@linux.dev>
Date:   Wed, 30 Aug 2023 19:15:29 +0800
From:   Sui Jingfeng <sui.jingfeng@...ux.dev>
To:     Bjorn Helgaas <bhelgaas@...gle.com>,
        Gerd Hoffmann <kraxel@...hat.com>,
        Gurchetan Singh <gurchetansingh@...omium.org>,
        Chia-I Wu <olvaffe@...il.com>
Cc:     dri-devel@...ts.freedesktop.org, linux-pci@...r.kernel.org,
        linux-kernel@...r.kernel.org,
        virtualization@...ts.linux-foundation.org,
        Sui Jingfeng <suijingfeng@...ngson.cn>,
        "Maciej W. Rozycki" <macro@...am.me.uk>,
        Mario Limonciello <mario.limonciello@....com>
Subject: [-next 2/5] PCI/VGA: Deal with VGA devices

From: Sui Jingfeng <suijingfeng@...ngson.cn>

VGAARB only cares about PCI(e) VGA devices, thus filtering out unqualified
devices as early as possible. This also means that deleting a non-VGA
device snooped won't unnecessarily call into vga_arbiter_del_pci_device()
function. By using the newly implemented pci_is_vga(),
PCI(e) with PCI_CLASS_NOT_DEFINED_VGA class code will also be handled.

Cc: "Maciej W. Rozycki" <macro@...am.me.uk>
Reviewed-by: Mario Limonciello <mario.limonciello@....com>
Signed-off-by: Sui Jingfeng <suijingfeng@...ngson.cn>
---
 drivers/pci/vgaarb.c | 19 +++++++++----------
 1 file changed, 9 insertions(+), 10 deletions(-)

diff --git a/drivers/pci/vgaarb.c b/drivers/pci/vgaarb.c
index 5e6b1eb54c64..ef8fe685de67 100644
--- a/drivers/pci/vgaarb.c
+++ b/drivers/pci/vgaarb.c
@@ -764,10 +764,6 @@ 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) {
@@ -1503,6 +1499,9 @@ static int pci_notify(struct notifier_block *nb, unsigned long action,
 
 	vgaarb_dbg(dev, "%s\n", __func__);
 
+	if (!pci_is_vga(pdev))
+		return 0;
+
 	/*
 	 * For now, we're only interested in devices added and removed.
 	 * I didn't test this thing here, so someone needs to double check
@@ -1537,8 +1536,8 @@ 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)
@@ -1547,11 +1546,11 @@ static int __init vga_arb_device_init(void)
 	bus_register_notifier(&pci_bus_type, &pci_notifier);
 
 	/* Add all VGA class PCI devices 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);
+	do {
+		pdev = pci_get_subsys(PCI_ANY_ID, PCI_ANY_ID, PCI_ANY_ID, PCI_ANY_ID, pdev);
+		if (pci_is_vga(pdev))
+			vga_arbiter_add_pci_device(pdev);
+	} while (pdev);
 
 	pr_info("loaded\n");
 	return rc;
-- 
2.34.1