[PATCH v6 2/3] drm/hyperv: Handle feature change message from device

[Deepak Rawat <drawat.floss@gmail.com>]

Virtual device inform if screen update is needed or not with
SYNTHVID_FEATURE_CHANGE message. Handle this message to set dirt_needed
flag.

Suggested-by: Dexuan Cui <decui@microsoft.com>
Signed-off-by: Deepak Rawat <drawat.floss@gmail.com>
Acked-by: Thomas Zimmermann <tzimmermann@suse.de>
---
 drivers/gpu/drm/hyperv/hyperv_drm.h       | 1 +
 drivers/gpu/drm/hyperv/hyperv_drm_drv.c   | 2 ++
 drivers/gpu/drm/hyperv/hyperv_drm_proto.c | 7 +++++++
 3 files changed, 10 insertions(+)

diff --git a/drivers/gpu/drm/hyperv/hyperv_drm.h b/drivers/gpu/drm/hyperv/hyperv_drm.h
index e1d1fdea96f2..886add4f9cd0 100644
--- a/drivers/gpu/drm/hyperv/hyperv_drm.h
+++ b/drivers/gpu/drm/hyperv/hyperv_drm.h
@@ -29,6 +29,7 @@ struct hyperv_drm_device {
 	struct completion wait;
 	u32 synthvid_version;
 	u32 mmio_megabytes;
+	bool dirt_needed;
 
 	u8 init_buf[VMBUS_MAX_PACKET_SIZE];
 	u8 recv_buf[VMBUS_MAX_PACKET_SIZE];
diff --git a/drivers/gpu/drm/hyperv/hyperv_drm_drv.c b/drivers/gpu/drm/hyperv/hyperv_drm_drv.c
index beb53068fa0d..eb06c92c4bfd 100644
--- a/drivers/gpu/drm/hyperv/hyperv_drm_drv.c
+++ b/drivers/gpu/drm/hyperv/hyperv_drm_drv.c
@@ -198,6 +198,8 @@ static int hyperv_vmbus_probe(struct hv_device *hdev,
 	if (ret)
 		drm_warn(dev, "Failed to update vram location.\n");
 
+	hv->dirt_needed = true;
+
 	ret = hyperv_mode_config_init(hv);
 	if (ret)
 		goto err_vmbus_close;
diff --git a/drivers/gpu/drm/hyperv/hyperv_drm_proto.c b/drivers/gpu/drm/hyperv/hyperv_drm_proto.c
index 00c4cc2db605..6d4bdccfbd1a 100644
--- a/drivers/gpu/drm/hyperv/hyperv_drm_proto.c
+++ b/drivers/gpu/drm/hyperv/hyperv_drm_proto.c
@@ -301,8 +301,12 @@ int hyperv_update_situation(struct hv_device *hdev, u8 active, u32 bpp,
 
 int hyperv_update_dirt(struct hv_device *hdev, struct drm_rect *rect)
 {
+	struct hyperv_drm_device *hv = hv_get_drvdata(hdev);
 	struct synthvid_msg msg;
 
+	if (!hv->dirt_needed)
+		return 0;
+
 	memset(&msg, 0, sizeof(struct synthvid_msg));
 
 	msg.vid_hdr.type = SYNTHVID_DIRT;
@@ -387,6 +391,9 @@ static void hyperv_receive_sub(struct hv_device *hdev)
 		complete(&hv->wait);
 		return;
 	}
+
+	if (msg->vid_hdr.type == SYNTHVID_FEATURE_CHANGE)
+		hv->dirt_needed = msg->feature_chg.is_dirt_needed;
 }
 
 static void hyperv_receive(void *ctx)
-- 
2.31.1