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(-) base-commit: 43cc31da9146f9ce60e4a03d96ef0807c2cdac94 -- 2.34.1
