[PATCH i-g-t] tests/intel/kms_pm_backlight: Brightness test during DPMS on and off

[Mohammed Thasleem <mohammed.thasleem@intel.com>]

Set brightness by deviding max brightness, store and read it back.
The actual brightness should be same during DPMS on and off cycle.

v2: Update test path and testplan documentation.

Signed-off-by: Mohammed Thasleem <mohammed.thasleem@intel.com>
---
 tests/intel/kms_pm_backlight.c | 41 ++++++++++++++++++++++++++++++++++
 1 file changed, 41 insertions(+)

diff --git a/tests/intel/kms_pm_backlight.c b/tests/intel/kms_pm_backlight.c
index 2e691dab0..107b7d668 100644
--- a/tests/intel/kms_pm_backlight.c
+++ b/tests/intel/kms_pm_backlight.c
@@ -64,6 +64,10 @@
  * SUBTEST: fade-with-suspend
  * Description: Test the fade with suspend.
  * Functionality: backlight, suspend
+ *
+ * SUBTEST: brightness-with-dpms
+ * Description: test brightness with dpms on and off cycle.
+ * Functionality: backlight, backlight
  */
 
 struct context {
@@ -217,6 +221,32 @@ check_suspend(igt_output_t *output)
 	igt_system_suspend_autoresume(SUSPEND_STATE_MEM, SUSPEND_TEST_NONE);
 }
 
+static void check_dpms_cycle(igt_display_t *display, igt_output_t *output, struct context *context)
+{
+	int max, val_1, val_2;
+
+	backlight_read(&max, "max_brightness", context);
+	igt_assert(max);
+
+	backlight_write(max / 2, "brightness", context);
+	backlight_read(&val_1, "actual_brightness", context);
+
+	igt_require(igt_setup_runtime_pm(output->display->drm_fd));
+
+	kmstest_set_connector_dpms(output->display->drm_fd,
+				   output->config.connector,
+				   DRM_MODE_DPMS_OFF);
+	igt_require(igt_wait_for_pm_status(IGT_RUNTIME_PM_STATUS_SUSPENDED));
+
+	kmstest_set_connector_dpms(output->display->drm_fd,
+				   output->config.connector,
+				   DRM_MODE_DPMS_ON);
+	igt_assert(igt_wait_for_pm_status(IGT_RUNTIME_PM_STATUS_ACTIVE));
+
+	backlight_read(&val_2, "actual_brightness", context);
+	igt_assert_eq(val_1, val_2);
+}
+
 static void test_cleanup(igt_display_t *display, igt_output_t *output)
 {
 	igt_output_set_pipe(output, PIPE_NONE);
@@ -354,6 +384,17 @@ igt_main
 		}
 	}
 
+	igt_describe("test brightness with dpms on and off cycle");
+	igt_subtest_with_dynamic("brightness-with-dpms") {
+		for (int j = 0; j < (dual_edp ? 2 : 1); j++) {
+			test_setup(display, &contexts->output[j]);
+			igt_dynamic_f("%s", igt_output_name(contexts[j].output)) {
+				check_dpms_cycle(&display, &contexts->output[j], &contexts[j]);
+				test_cleanup(&display, &contexts->output[j]);
+			}
+		}
+	}
+
 	igt_fixture {
 		/* Restore old brightness */
 		for (i = 0; i < (dual_edp ? 2 : 1); i++)
-- 
2.25.1