On Wed, Aug 30, 2023 at 07:15:27PM +0800, Sui Jingfeng wrote: > From: Sui Jingfeng <suijingfeng@xxxxxxxxxxx> > > The PCI code and ID assignment specification defined four types of > display controllers for the display base class(03h), and the devices > with 0x00h sub-class code are VGA devices. VGA devices with programming > interface 0x00 is VGA-compatible, VGA devices with programming interface > 0x01 are 8514-compatible controllers. Besides, PCI_CLASS_NOT_DEFINED_VGA > is defined to provide backward compatibility for devices that were built > before the class code field was defined. Thus, PCI(e) device with the > PCI_CLASS_NOT_DEFINED_VGA class code should also be handled as the normal > VGA-compatible devices. > > Compared with the "if ((pdev->class >> 8) != PCI_CLASS_DISPLAY_VGA)" code, > the newly implemented pci_is_vga() is shorter and straightforward. So it > is more easy to use. It is designed as a inline function, the more common > case "if ((pdev->class >> 8) == PCI_CLASS_DISPLAY_VGA))" is put before the > less common case "if ((pdev->class >> 8) == PCI_CLASS_NOT_DEFINED_VGA)", > so there should no performance penalty. > > Sui Jingfeng (5): > PCI: Add the pci_is_vga() helper > PCI/VGA: Deal with VGA devices > PCI/sysfs: Use pci_is_vga() helper > drm/virgpu: Switch to pci_is_vga() > drm/qxl: Switch to pci_is_vga() > > drivers/gpu/drm/qxl/qxl_drv.c | 11 +++-------- > drivers/gpu/drm/virtio/virtgpu_drv.c | 2 +- > drivers/pci/pci-sysfs.c | 6 +++--- > drivers/pci/vgaarb.c | 19 +++++++++---------- > include/linux/pci.h | 27 +++++++++++++++++++++++++++ > 5 files changed, 43 insertions(+), 22 deletions(-) I applied these on pci/vga for v6.7, thanks! Please take a look at https://git.kernel.org/pub/scm/linux/kernel/git/pci/pci.git/log/?h=vga and let me know if I broke anything because I changed a few things; interdiff below: diff --git a/drivers/pci/pci-sysfs.c b/drivers/pci/pci-sysfs.c index 522708938563..252ee29fd697 100644 --- a/drivers/pci/pci-sysfs.c +++ b/drivers/pci/pci-sysfs.c @@ -1551,9 +1551,8 @@ static umode_t pci_dev_attrs_are_visible(struct kobject *kobj, struct device *dev = kobj_to_dev(kobj); struct pci_dev *pdev = to_pci_dev(dev); - if (a == &dev_attr_boot_vga.attr) - if (pci_is_vga(pdev)) - return a->mode; + if (a == &dev_attr_boot_vga.attr && pci_is_vga(pdev)) + return a->mode; return 0; } diff --git a/drivers/pci/vgaarb.c b/drivers/pci/vgaarb.c index ef8fe685de67..feca96fc4255 100644 --- a/drivers/pci/vgaarb.c +++ b/drivers/pci/vgaarb.c @@ -1499,6 +1499,7 @@ static int pci_notify(struct notifier_block *nb, unsigned long action, vgaarb_dbg(dev, "%s\n", __func__); + /* Only deal with VGA class devices */ if (!pci_is_vga(pdev)) return 0; @@ -1536,8 +1537,8 @@ 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) @@ -1546,11 +1547,13 @@ static int __init vga_arb_device_init(void) bus_register_notifier(&pci_bus_type, &pci_notifier); /* Add all VGA class PCI devices by default */ - do { - pdev = pci_get_subsys(PCI_ANY_ID, PCI_ANY_ID, PCI_ANY_ID, PCI_ANY_ID, pdev); + pdev = NULL; + while ((pdev = + pci_get_subsys(PCI_ANY_ID, PCI_ANY_ID, PCI_ANY_ID, + PCI_ANY_ID, pdev)) != NULL) { if (pci_is_vga(pdev)) vga_arbiter_add_pci_device(pdev); - } while (pdev); + } pr_info("loaded\n"); return rc; diff --git a/include/linux/pci.h b/include/linux/pci.h index 53e24e31c27e..7bab234391cb 100644 --- a/include/linux/pci.h +++ b/include/linux/pci.h @@ -714,23 +714,20 @@ static inline bool pci_is_bridge(struct pci_dev *dev) } /** - * The PCI code and ID assignment specification defined four types of - * display controllers for the display base class(03h), and the devices - * with 0x00h sub-class code are VGA devices. VGA devices with programming - * interface 0x00 is VGA-compatible, VGA devices with programming interface - * 0x01 are 8514-compatible controllers. Besides, PCI_CLASS_NOT_DEFINED_VGA - * is defined to provide backward compatibility for devices that were built - * before the class code field was defined. This means that it belong to the - * VGA devices category also. + * pci_is_vga - check if the PCI device is a VGA device * - * Returns: - * true if the PCI device is a VGA device, false otherwise. + * The PCI Code and ID Assignment spec, r1.15, secs 1.4 and 1.1, define + * VGA Base Class and Sub-Classes: + * + * 03 00 PCI_CLASS_DISPLAY_VGA VGA-compatible or 8514-compatible + * 00 01 PCI_CLASS_NOT_DEFINED_VGA VGA-compatible (before Class Code) + * + * Return true if the PCI device is a VGA device and uses the legacy VGA + * resources ([mem 0xa0000-0xbffff], [io 0x3b0-0x3bb], [io 0x3c0-0x3df] and + * aliases). */ static inline bool pci_is_vga(struct pci_dev *pdev) { - if (!pdev) - return false; - if ((pdev->class >> 8) == PCI_CLASS_DISPLAY_VGA) return true;
