[why & how]
For amdgpu PSR-SU validation, we'd create and test cursor update
use case as well. To emulate a mouse-like cursor movement, we'd
define a helper to draw a cursor pattern.

- helper draw the cursor pattern as an 45-degrees rotated arrow
- for the region of arrow, set alpha to 1 to make cursor foreground
  and always on the top
- for rest of the non-arrow region, set alpha to 0 to make it as
  background

Cc: Rodrigo Siqueira <rodrigo.siqueira@amd.com>
Cc: Harry Wentland <harry.wentland@amd.com>
Cc: Leo Li <sunpeng.li@amd.com>
Cc: Jay Pillai <aurabindo.pillai@amd.com>
Cc: Wayne Lin <wayne.lin@amd.com>

Signed-off-by: David Zhang <dingchen.zhang@amd.com>
---
 tests/amdgpu/amd_psr.c | 47 ++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 47 insertions(+)

diff --git a/tests/amdgpu/amd_psr.c b/tests/amdgpu/amd_psr.c
index d4bfb7bb..e3a2cb4a 100644
--- a/tests/amdgpu/amd_psr.c
+++ b/tests/amdgpu/amd_psr.c
@@ -81,6 +81,53 @@ static void draw_color_alpha(igt_fb_t *fb, int x, int y, int w, int h,
         igt_put_cairo_ctx(cr);
 }
 
+/* draw a cursor pattern assuming the FB given is square w/ FORMAT ARGB */
+static void draw_color_cursor(igt_fb_t *fb, int size, double r, double g, double b)
+{
+       cairo_t *cr = igt_get_cairo_ctx(fb->fd, fb);
+       int x, y, line_w;
+
+       cairo_set_operator(cr, CAIRO_OPERATOR_SOURCE);
+
+       /*
+        * draw cursor
+        * recall that alpha blending value:
+        * - 0, output pixel is the background
+        * - 1, output pixel is simply the foreground
+        * - (0, 1), mix of background + foreground
+        */
+
+       /* set cursor FB to background first */
+       igt_paint_color_alpha(cr, 0, 0, size, size, 1.0, 1.0, 1.0, .0);
+
+       /*
+        * draw cursur pattern w/ alpha set to 1
+        * - 1. draw triangle part
+        * - 2. draw rectangle part
+        */
+       for (x = y = 0, line_w = size / 2; line_w > 0; ++y, --line_w)
+               igt_paint_color_alpha(cr, x, y, line_w, 1, r, g, b, 1.0);
+
+       /*
+        * draw rectangle part, split into three geometry parts
+        * - triangle
+        * - rhombus
+        * - reversed triangle
+        */
+       for (x = size * 3 / 8, y = size / 8, line_w = 1; y < size * 3 / 8; --x, ++y, line_w += 2)
+               igt_paint_color_alpha(cr, x, y, line_w, 1, r, g, b, 1.0);
+
+       for (x = size / 8, y = size * 3 / 8; y < size * 3 / 4; ++x, ++y)
+               igt_paint_color_alpha(cr, x, y, line_w, 1, r, g, b, 1.0);
+
+       for (; line_w > 0; ++x, ++y, line_w -= 2)
+               igt_paint_color_alpha(cr, x, y, line_w, 1, r, g, b, 1.0);
+
+       cairo_set_operator(cr, CAIRO_OPERATOR_OVER);
+
+       igt_put_cairo_ctx(cr);
+}
+
 /* Common test setup. */
 static void test_init(data_t *data)
 {
--
2.25.1