[Intel-gfx] [PATCH i-g-t 2/2] tests/pm_backlight: Enable all possible outputs to allow tests to succeed.

[Maarten Lankhorst]

If all outputs are disabled before this test is run, then the test
will fail because actual_brightness stays at 0 instead of the value
of the desired brightness. Fix this by enabling all outputs at the
start of this test.

Sample failure:
IGT-Version: 1.20-g01c550a27986 (x86_64) (Linux: 4.14.0-rc3-fbconhax+ x86_64)
(pm_backlight:1203) CRITICAL: Test assertion failure function test_and_verify, file pm_backlight.c:111:
(pm_backlight:1203) CRITICAL: Failed assertion: ({ typeof(0) _a = (0); typeof(val - tolerance) _b = (val - tolerance); _a > _b ? _a : _b; }) <= result
(pm_backlight:1203) CRITICAL: error: 91200 > 0

Signed-off-by: Maarten Lankhorst <maarten.lankhorst at linux.intel.com>
---
 tests/pm_backlight.c | 27 +++++++++++++++++++++++++++
 1 file changed, 27 insertions(+)

diff --git a/tests/pm_backlight.c b/tests/pm_backlight.c
index 8258d4e4c124..b365c7f6dc60 100644
--- a/tests/pm_backlight.c
+++ b/tests/pm_backlight.c
@@ -155,13 +155,37 @@ igt_main
 {
 	struct context context = {0};
 	int old;
+	igt_display_t display;
 
 	igt_skip_on_simulation();
 
 	igt_fixture {
+		enum pipe pipe;
+
 		/* Get the max value and skip the whole test if sysfs interface not available */
 		igt_skip_on(backlight_read(&old, "brightness"));
 		igt_assert(backlight_read(&context.max, "max_brightness") > -1);
+
+		/*
+		 * Backlight tests requires the output to be enabled,
+		 * try to enable all.
+		 */
+		kmstest_set_vt_graphics_mode();
+		igt_display_init(&display, drm_open_driver(DRIVER_INTEL));
+
+		for_each_pipe(&display, pipe) {
+			igt_output_t *output;
+
+			for_each_valid_output_on_pipe(&display, pipe, output) {
+				if (output->pending_pipe != PIPE_NONE)
+					continue;
+
+				igt_output_set_pipe(output, pipe);
+				break;
+			}
+		}
+
+		igt_display_commit2(&display, display.is_atomic ? COMMIT_ATOMIC : COMMIT_LEGACY);
 	}
 
 	igt_subtest("basic-brightness")
@@ -174,5 +198,8 @@ igt_main
 	igt_fixture {
 		/* Restore old brightness */
 		backlight_write(old, "brightness");
+
+		igt_display_fini(&display);
+		close(display.drm_fd);
 	}
 }
-- 
2.14.1