[PATCH RESEND v2 2/3] drm/vkms: add support for multiple overlay planes

[José Expósito]

Create 8 overlay planes instead of 1 when the "enable_overlay" module
parameter is set.

The following igt-gpu-tools tests were executed without finding
regressions. Notice than the numbers are identical:

                    |     master branch     |      this  patch      |
                    | SUCCESS | SKIP | FAIL | SUCCESS | SKIP | FAIL |
 kms_atomic         |      10 |   02 |   00 |      10 |   02 |   00 |
 kms_plane_cursor   |      09 |   45 |   00 |      09 |   45 |   00 |
 kms_plane_multiple |      01 |   23 |   00 |      01 |   23 |   00 |
 kms_writeback      |      04 |   00 |   00 |      04 |   00 |   00 |

Signed-off-by: José Expósito <jose.exposito89 at gmail.com>

---

v2:

 - Set the number of overlay planes as a constant instead of as a
   module parameter (Melissa Wen)

 - Add a test results in the commit message (Melissa Wen)
---
 drivers/gpu/drm/vkms/vkms_drv.h    | 2 ++
 drivers/gpu/drm/vkms/vkms_output.c | 9 ++++++---
 2 files changed, 8 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/vkms/vkms_drv.h b/drivers/gpu/drm/vkms/vkms_drv.h
index d48c23d40ce5..9496fdc900b8 100644
--- a/drivers/gpu/drm/vkms/vkms_drv.h
+++ b/drivers/gpu/drm/vkms/vkms_drv.h
@@ -20,6 +20,8 @@
 #define XRES_MAX  8192
 #define YRES_MAX  8192
 
+#define NUM_OVERLAY_PLANES 8
+
 struct vkms_writeback_job {
 	struct dma_buf_map map[DRM_FORMAT_MAX_PLANES];
 	struct dma_buf_map data[DRM_FORMAT_MAX_PLANES];
diff --git a/drivers/gpu/drm/vkms/vkms_output.c b/drivers/gpu/drm/vkms/vkms_output.c
index 2e805b2d36ae..ba0e82ae549a 100644
--- a/drivers/gpu/drm/vkms/vkms_output.c
+++ b/drivers/gpu/drm/vkms/vkms_output.c
@@ -57,15 +57,18 @@ int vkms_output_init(struct vkms_device *vkmsdev, int index)
 	struct vkms_plane *primary, *cursor = NULL;
 	int ret;
 	int writeback;
+	unsigned int n;
 
 	primary = vkms_plane_init(vkmsdev, DRM_PLANE_TYPE_PRIMARY, index);
 	if (IS_ERR(primary))
 		return PTR_ERR(primary);
 
 	if (vkmsdev->config->overlay) {
-		ret = vkms_add_overlay_plane(vkmsdev, index, crtc);
-		if (ret)
-			return ret;
+		for (n = 0; n < NUM_OVERLAY_PLANES; n++) {
+			ret = vkms_add_overlay_plane(vkmsdev, index, crtc);
+			if (ret)
+				return ret;
+		}
 	}
 
 	if (vkmsdev->config->cursor) {
-- 
2.25.1