[igt-dev] [PATCH i-g-t v3 4/4] tests/kms_frontbuffer_tracking: Remove redundant modesets during subtest start.

[Maarten Lankhorst]

Hey,

Op 27-02-18 om 09:52 schreef Maarten Lankhorst:
> CRC capturing enables the display, then disables it again. With
> igt_display we can use igt_display_reset to restore the original state,
> without committing it to the hw.
>
> All subtests first set their own state anyway, so we can save up on
> the number of commits.

I patched igt_kms to report the number of modesets..

Without this patch running ./kms_frontbuffer_tracking on a 2 output system (f2-snb-2600, forced VGA-1 enabled):
Performed 382 modesets

With this patch on a 2 output system:
Performed 23 modesets

On geminilake this means we save a lot of time, so could someone review this series?

Also for comparison, single output enabled, fbc-1p-rte:
Unpatched:
Performed 4 modesets

Patched:
Performed 2 modesets

Hack below:

---8<---
diff --git a/lib/igt_kms.c b/lib/igt_kms.c
index 2d57369fe558..dfefe1f887ec 100644
--- a/lib/igt_kms.c
+++ b/lib/igt_kms.c
@@ -2154,6 +2154,8 @@ void igt_display_fini(igt_display_t *display)
 {
 	int i;
 
+	igt_info("Performed %u modesets\n", display->modesets);
+
 	for (i = 0; i < display->n_pipes; i++)
 		igt_pipe_fini(&display->pipes[i]);
 
@@ -3196,8 +3198,23 @@ static int do_display_commit(igt_display_t *display,
 	igt_display_refresh(display);
 
 	if (s == COMMIT_ATOMIC) {
-		ret = igt_atomic_commit(display, DRM_MODE_ATOMIC_ALLOW_MODESET, NULL);
+		ret = igt_atomic_commit(display, 0, NULL);
+
+		if (ret == -EINVAL) {
+			ret = igt_atomic_commit(display, DRM_MODE_ATOMIC_ALLOW_MODESET, NULL);
+			if (!ret)
+				display->modesets++;
+		}
+
 	} else {
+		ret = igt_atomic_commit(display, DRM_MODE_ATOMIC_TEST_ONLY, NULL);
+		if (ret == -EINVAL) {
+			ret = igt_atomic_commit(display, DRM_MODE_ATOMIC_TEST_ONLY | DRM_MODE_ATOMIC_ALLOW_MODESET, NULL);
+			if (!ret)
+				display->modesets++;
+			ret = 0;
+		}
+
 		for_each_pipe(display, pipe) {
 			igt_pipe_t *pipe_obj = &display->pipes[pipe];
 
diff --git a/lib/igt_kms.h b/lib/igt_kms.h
index f27e22088ce2..718ea8ce0497 100644
--- a/lib/igt_kms.h
+++ b/lib/igt_kms.h
@@ -357,6 +357,7 @@ struct igt_display {
 	bool has_cursor_plane;
 	bool is_atomic;
 	bool first_commit;
+	int modesets;
 };
 
 void igt_display_init(igt_display_t *display, int drm_fd);