[RFC PATCH v2 2/3] drm/i915/gvt: Introduce enable_direct_flip attribute

[Tina Zhang]

This attribute is introduced to work as a switch of the gvt-g vGPU direct
flip function. Userspace can simply switch on/off the direct flip
function by echoing 1/0 to this attributte.

Signed-off-by: Tina Zhang <tina.zhang at intel.com>
---
 drivers/gpu/drm/i915/gvt/kvmgt.c | 38 ++++++++++++++++++++++++++++++++++++++
 1 file changed, 38 insertions(+)

diff --git a/drivers/gpu/drm/i915/gvt/kvmgt.c b/drivers/gpu/drm/i915/gvt/kvmgt.c
index a68addf..2911818 100644
--- a/drivers/gpu/drm/i915/gvt/kvmgt.c
+++ b/drivers/gpu/drm/i915/gvt/kvmgt.c
@@ -1581,12 +1581,50 @@ hw_id_show(struct device *dev, struct device_attribute *attr,
 	return sprintf(buf, "\n");
 }
 
+static ssize_t
+enable_direct_flip_show(struct device *dev, struct device_attribute *attr,
+	 char *buf)
+{
+	struct mdev_device *mdev = mdev_from_dev(dev);
+
+	if (mdev) {
+		struct intel_vgpu *vgpu = (struct intel_vgpu *)
+			mdev_get_drvdata(mdev);
+		return sprintf(buf, "%u\n",
+			       vgpu->display.shadow_fbs.enable_direct_flip);
+	}
+	return sprintf(buf, "\n");
+}
+
+static ssize_t
+enable_direct_flip_store(struct device *dev, struct device_attribute *attr,
+			     const char *buf, size_t n)
+{
+	struct mdev_device *mdev = mdev_from_dev(dev);
+	ssize_t ret;
+	u32 val;
+
+	ret = kstrtou32(buf, 0, &val);
+	if (ret)
+		return ret;
+
+	if (mdev) {
+		struct intel_vgpu *vgpu = (struct intel_vgpu *)
+			mdev_get_drvdata(mdev);
+		vgpu->display.shadow_fbs.enable_direct_flip = !!val;
+	}
+
+	return n;
+}
+
 static DEVICE_ATTR_RO(vgpu_id);
 static DEVICE_ATTR_RO(hw_id);
+static DEVICE_ATTR_RW(enable_direct_flip);
 
 static struct attribute *intel_vgpu_attrs[] = {
 	&dev_attr_vgpu_id.attr,
 	&dev_attr_hw_id.attr,
+	&dev_attr_enable_direct_flip.attr,
 	NULL
 };
 
-- 
2.7.4