Messages in this thread | | | Date | Fri, 6 Oct 2023 19:22:42 +0800 | Subject | Re: [-next 4/5] drm/virgpu: Switch to pci_is_vga() | From | Sui Jingfeng <> |
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Hi,
On 2023/10/6 05:57, Bjorn Helgaas wrote: > In subject: "drm/virtio" to match previous history. > > On Wed, Aug 30, 2023 at 07:15:31PM +0800, Sui Jingfeng wrote: >> From: Sui Jingfeng <suijingfeng@loongson.cn> >> >> Should be no functional change, just for cleanup purpose. >> >> Cc: David Airlie <airlied@redhat.com> >> Cc: Gerd Hoffmann <kraxel@redhat.com> >> Cc: Gurchetan Singh <gurchetansingh@chromium.org> >> Cc: Chia-I Wu <olvaffe@gmail.com> >> Cc: Daniel Vetter <daniel@ffwll.ch> >> Signed-off-by: Sui Jingfeng <suijingfeng@loongson.cn> >> --- >> drivers/gpu/drm/virtio/virtgpu_drv.c | 2 +- >> 1 file changed, 1 insertion(+), 1 deletion(-) >> >> diff --git a/drivers/gpu/drm/virtio/virtgpu_drv.c b/drivers/gpu/drm/virtio/virtgpu_drv.c >> index add075681e18..3a368304475a 100644 >> --- a/drivers/gpu/drm/virtio/virtgpu_drv.c >> +++ b/drivers/gpu/drm/virtio/virtgpu_drv.c >> @@ -51,7 +51,7 @@ static int virtio_gpu_pci_quirk(struct drm_device *dev) >> { >> struct pci_dev *pdev = to_pci_dev(dev->dev); >> const char *pname = dev_name(&pdev->dev); >> - bool vga = (pdev->class >> 8) == PCI_CLASS_DISPLAY_VGA; >> + bool vga = pci_is_vga(pdev); > This *is* a functional change: Previously "vga" was only true for > PCI_CLASS_DISPLAY_VGA (0x0300). Now it will be true for both > PCI_CLASS_DISPLAY_VGA (0x0300) and PCI_CLASS_DISPLAY_OTHER (0x0380). > > Is that desirable? I can't tell. Maybe the GPU folks will chime in. >
Yes, the vga variable still will be "true" for the PCI_CLASS_DISPLAY_VGA (0x0300) class code, and this is the major case. But the devices with PCI_CLASS_NOT_DEFINED_VGA class code are quite uncommon, and virtio gpu is virtual GPU driver, It is unlikely that the QEMU to emulate a old device with PCI_CLASS_NOT_DEFINED_VGA class code. I means that there no reason to do so. Am I correct? Is there anyone know more?
For virtio virtual GPU driver, I would like to drop this patch, if no one response.
We probably only need to consider PCI_CLASS_NOT_DEFINED_VGA case for the real (probably old) hardware device. It do exists, as Maciej mention at [1].
[1] https://lkml.org/lkml/2023/6/18/315
>> int ret; >> >> DRM_INFO("pci: %s detected at %s\n", >> -- >> 2.34.1 >>
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