Hi,
On 2023/7/20 02:26, Bjorn Helgaas wrote:
On Tue, Jul 11, 2023 at 09:43:50PM +0800, Sui Jingfeng wrote:
[...]
Reviewed-by: Mario Limonciello <mario.limonciello@xxxxxxx>
Signed-off-by: Sui Jingfeng <suijingfeng@xxxxxxxxxxx>
I do not see Mario's Reviewed-by on the list. I do see Mario's
Reviewed-by [2] for a previous version, but that version added this in
pci_notify():
+ if (pdev->class != PCI_CLASS_DISPLAY_VGA << 8)
+ return 0;
while this version adds:
+ if ((pdev->class >> 8) != PCI_CLASS_DISPLAY_VGA)
+ return 0;
It's OK to carry a review to future versions if there are
insignificant changes, but this is a functional change that seems
significant to me. The first matches only 0x030000, while the second
discards the low eight bits so it matches 0x0300XX.
Yes, you are right.
But I suddenly realized that this may deserve another patch, desperate
trivial.
What this version adds here is *same* before this patch set is applied.
My explanation about the minor tweak being made before this version and
previous version
is that I want to keep my patch *less distraction*.
The major functional gains(benefit) is that we filter non VGA compatible
devices out.
As a start point, I should keep one patch do one thing (do one thing and
do it well).
On the other hand, even though the lest significant 8 but if pdev->class
is really matter.
I think I still need to wait the things(a bug emerged, for example)
became clear.
Instead of cleanup all potential problems with obvious motivation.
I think Mario will accept my explanation.
[1] https://lore.kernel.org/r/20230718231400.GA496927@bhelgaas
[2] https://lore.kernel.org/all/5b6fdf65-b354-94a9-f883-be820157efad@xxxxxxx/
---
drivers/pci/vgaarb.c | 25 +++++++++++++------------
1 file changed, 13 insertions(+), 12 deletions(-)
diff --git a/drivers/pci/vgaarb.c b/drivers/pci/vgaarb.c
index c1bc6c983932..021116ed61cb 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) {
@@ -1502,6 +1498,10 @@ static int pci_notify(struct notifier_block *nb, unsigned long action,
vgaarb_dbg(dev, "%s\n", __func__);
+ /* Deal with VGA compatible devices only */
+ if ((pdev->class >> 8) != PCI_CLASS_DISPLAY_VGA)
+ 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
* cases of hotplugable vga cards. */
@@ -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)
@@ -1543,13 +1543,14 @@ static int __init vga_arb_device_init(void)
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);
+ /*
+ * We add all PCI VGA compatible devices in the arbiter by default
+ */
+ do {
+ pdev = pci_get_class(PCI_CLASS_DISPLAY_VGA << 8, pdev);
+ if (pdev)
+ vga_arbiter_add_pci_device(pdev);
+ } while (pdev);
pr_info("loaded\n");
return rc;
--
2.25.1
