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.
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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