On Sun, Sep 26, 2021 at 03:15:39PM +0800, Zhenneng Li wrote:
> Add writing attribute for boot_vga sys node,
> so we can config default video display
> output dynamically when there are two video
> cards on a machine.
>
> Xorg server will determine running on which
> video card based on boot_vga node's value.
When you repost this, please take a look at the git commit log history
and make yours similar. Specifically, the subject should start with a
capital letter, and the body should be rewrapped to fill 75
characters.
Please contrast this with the existing VGA arbiter. See
Documentation/gpu/vgaarbiter.rst. It sounds like this may overlap
with the VGA arbiter functionality, so this should explain why we need
both and how they interact.
> Signed-off-by: Zhenneng Li <lizhenneng@xxxxxxxxxx>
> ---
> drivers/pci/pci-sysfs.c | 24 +++++++++++++++++++++++-
> 1 file changed, 23 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/pci/pci-sysfs.c b/drivers/pci/pci-sysfs.c
> index 7bbf2673c7f2..a6ba19ce7adb 100644
> --- a/drivers/pci/pci-sysfs.c
> +++ b/drivers/pci/pci-sysfs.c
> @@ -664,7 +664,29 @@ static ssize_t boot_vga_show(struct device *dev, struct device_attribute *attr,
> !!(pdev->resource[PCI_ROM_RESOURCE].flags &
> IORESOURCE_ROM_SHADOW));
> }
> -static DEVICE_ATTR_RO(boot_vga);
> +
> +static ssize_t boot_vga_store(struct device *dev, struct device_attribute *attr,
> + const char *buf, size_t count)
> +{
> + unsigned long val;
> + struct pci_dev *pdev = to_pci_dev(dev);
> + struct pci_dev *vga_dev = vga_default_device();
> +
> + if (kstrtoul(buf, 0, &val) < 0)
> + return -EINVAL;
> +
> + if (val != 1)
> + return -EINVAL;
> +
> + if (!capable(CAP_SYS_ADMIN))
> + return -EPERM;
> +
> + if (pdev != vga_dev)
> + vga_set_default_device(pdev);
> +
> + return count;
> +}
> +static DEVICE_ATTR_RW(boot_vga);
>
> static ssize_t pci_read_config(struct file *filp, struct kobject *kobj,
> struct bin_attribute *bin_attr, char *buf,
> --
> 2.25.1
>
>
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