On Mon, Jul 07, 2025 at 07:37:10PM +0200, Hans de Goede wrote:
> AMD64 boards with AGP support are so old that the agp_amd64_pci_table
> should be complete and there is no need to probe unlisted PCI devices,
> so lets completely remove support for probing unlisted PCI devices.
[...]
> --- a/drivers/char/agp/amd64-agp.c
> +++ b/drivers/char/agp/amd64-agp.c
> @@ -734,47 +733,10 @@ static struct pci_driver agp_amd64_pci_driver = {
> /* Not static due to IOMMU code calling it early. */
> int __init agp_amd64_init(void)
> {
> - struct pci_dev *pdev = NULL;
> - int err = 0;
> -
> if (agp_off)
> return -EINVAL;
>
> - err = pci_register_driver(&agp_amd64_pci_driver);
> - if (err < 0)
> - return err;
> -
> - if (agp_bridges_found == 0) {
> - if (!agp_try_unsupported && !agp_try_unsupported_boot) {
> - printk(KERN_INFO PFX "No supported AGP bridge
> found.\n");
> -#ifdef MODULE
> - printk(KERN_INFO PFX "You can try
> agp_try_unsupported=1\n");
> -#else
> - printk(KERN_INFO PFX "You can boot with
> agp=try_unsupported\n");
> -#endif
> - pci_unregister_driver(&agp_amd64_pci_driver);
> - return -ENODEV;
> - }
> -
> - /* First check that we have at least one AMD64 NB */
> - if (!amd_nb_num()) {
> - pci_unregister_driver(&agp_amd64_pci_driver);
> - return -ENODEV;
> - }
Here the PCI driver used to be unregistered if no AGP bridges were found
and successfully probed...
> -
> - /* Look for any AGP bridge */
> - for_each_pci_dev(pdev)
> - if (pci_find_capability(pdev, PCI_CAP_ID_AGP))
> - pci_add_dynid(&agp_amd64_pci_driver,
> - pdev->vendor, pdev->device,
> - pdev->subsystem_vendor,
> - pdev->subsystem_device, 0, 0, 0);
> - if (agp_bridges_found == 0) {
> - pci_unregister_driver(&agp_amd64_pci_driver);
> - err = -ENODEV;
> - }
> - }
> - return err;
> + return pci_register_driver(&agp_amd64_pci_driver);
> }
... and now the PCI driver will be kept around. Is that intentional?
Keeping the PCI driver around only makes sense if an AGP bridge is
later on hot-plugged. I guess that never happens with AGP bridges,
at least it's not supported by this driver so far.
Thanks,
Lukas
