[i-g-t, v6, 2/2] tests/kms_vrr: add support for full range refresh rate testing

[Lee Shawn C <shawn.c.lee@intel.com>]

Currently, kms_vrr tests fixed step increments within the VRR range.
To better validate hardware stability and potential issues across the
entire spectrum, this patch adds a 'full-range' testing mode.

When the full-range flag is enabled, the test will:
1. Iterate from the maximum to the minimum refresh rate (stepping by 1).
2. For standard testing, maintain the existing behavior of incrementing
   from minimum to maximum using the defined step size.

v2: Fix build failure by adding documentation for the new subtest.
v3: Remove unnecessary '!!' operator when assigning to bool.
v4: Add full-range (top-down/bottom-up) subtests to verify all supported
    RR within VRR range.
v5: Fix build failure for the new subtest.
v6: Revert commit 862eb176244f ("tests/kms_vrr: Start virtual RR test
    above midpoint to avoid mode fallback").

Cc: Naladala Ramanaidu <ramanaidu.naladala@intel.com>
Signed-off-by: Lee Shawn C <shawn.c.lee@intel.com>
---
 tests/kms_vrr.c | 126 ++++++++++++++++++++++++++++++++++++------------
 1 file changed, 95 insertions(+), 31 deletions(-)

diff --git a/tests/kms_vrr.c b/tests/kms_vrr.c
index 8f5c4a7c1501..b058a40df0a3 100644
--- a/tests/kms_vrr.c
+++ b/tests/kms_vrr.c
@@ -62,9 +62,11 @@
  * Description: Test to switch RR seamlessly without modeset.
  * Mega feature: General Display Features
  *
- * SUBTEST: seamless-rr-switch-virtual
- * Description: Test to create a Virtual Mode in VRR range and switch to it
- * 		without a full modeset.
+ * SUBTEST: seamless-rr-switch-virtual-top-down
+ * Description: Vrr seamless refresh rate switch for virtual modes using full range
+ *
+ * SUBTEST: seamless-rr-switch-virtual-bottom-up
+ * Description: Vrr seamless refresh rate switch for virtual modes using full range
  *
  * SUBTEST: lobf
  * Description: Test to validate link-off between active frames in non-psr
@@ -93,9 +95,10 @@ enum {
 	TEST_FLIPLINE = 1 << 3,
 	TEST_SEAMLESS_VRR = 1 << 4,
 	TEST_SEAMLESS_DRRS = 1 << 5,
-	TEST_SEAMLESS_VIRTUAL_RR = 1 << 6,
-	TEST_FASTSET = 1 << 7,
-	TEST_MAXMIN = 1 << 8,
+	TEST_SEAMLESS_VIRTUAL_RR_TOP_DOWN = 1 << 6,
+	TEST_SEAMLESS_VIRTUAL_RR_BOTTOM_UP = 1 << 7,
+	TEST_FASTSET = 1 << 8,
+	TEST_MAXMIN = 1 << 9,
 	TEST_LINK_OFF = 1 << 10,
 	TEST_NEGATIVE = 1 << 11,
 	TEST_FORCE_RR = 1 << 12,
@@ -227,7 +230,7 @@ low_rr_mode_with_same_res(igt_output_t *output, unsigned int vrr_min)
 	for (i = 0; i < connector->count_modes; i++)
 		if (connector->modes[i].hdisplay == mode.hdisplay &&
 		    connector->modes[i].vdisplay == mode.vdisplay &&
-		    connector->modes[i].clock < mode.clock &&
+		    connector->modes[i].clock <= mode.clock &&
 		    connector->modes[i].vrefresh < mode.vrefresh &&
 		    connector->modes[i].vrefresh >= vrr_min)
 			mode = connector->modes[i];
@@ -235,13 +238,57 @@ low_rr_mode_with_same_res(igt_output_t *output, unsigned int vrr_min)
 	return mode;
 }
 
-static void
-virtual_rr_vrr_range_mode(drmModeModeInfo *mode, float virtual_refresh_rate)
+static bool
+virtual_rr_vrr_range_mode(data_t *data, drmModeModeInfo *mode, float virtual_refresh_rate)
 {
 	uint64_t clock_hz = mode->clock * 1000;
+	uint16_t virtual_vtotal;
+
+	virtual_vtotal = clock_hz / (mode->htotal * virtual_refresh_rate);
+	if (is_intel_device(data->drm_fd) && virtual_vtotal > 8192) {
+		igt_info("VTotal (%d) already exceed 8192 at %fHz\n", virtual_vtotal, virtual_refresh_rate);
+		return false;
+	}
 
-	mode->vtotal = clock_hz / (mode->htotal * virtual_refresh_rate);
+	mode->vsync_start = virtual_vtotal - (mode->vtotal - mode->vsync_start);
+	mode->vsync_end   = virtual_vtotal - (mode->vtotal - mode->vsync_end);
+	mode->vtotal = virtual_vtotal;
 	mode->vrefresh = virtual_refresh_rate;
+	return true;
+}
+
+static drmModeModeInfo*
+get_selected_fixed_mode(igt_output_t *output, bool lowest)
+{
+	drmModeConnectorPtr connector = output->config.connector;
+	drmModeModeInfo *selected_mode = NULL;
+
+	for (int i = 0; i < connector->count_modes; i++) {
+		drmModeModeInfo *m = &connector->modes[i];
+
+		if (m->type & (DRM_MODE_TYPE_PREFERRED | DRM_MODE_TYPE_DRIVER)) {
+			if (!selected_mode) {
+				selected_mode = m;
+				continue;
+			}
+
+			if (lowest) {
+				if (m->vrefresh < selected_mode->vrefresh)
+					selected_mode = m;
+			} else {
+				if (m->vrefresh > selected_mode->vrefresh)
+					selected_mode = m;
+			}
+		}
+	}
+
+	if (selected_mode) {
+		igt_info("Found Target Fixed Mode: \"%s\" %dHz (vtotal: %d)\n",
+			 selected_mode->name, selected_mode->vrefresh, selected_mode->vtotal);
+		return selected_mode;
+	}
+
+	return NULL;
 }
 
 /* Read min and max vrr range from the connector debugfs. */
@@ -754,22 +801,28 @@ test_seamless_virtual_rr_basic(data_t *data, igt_crtc_t *crtc,
 			       igt_output_t *output, uint32_t flags)
 {
 	uint32_t result;
-	unsigned int vrefresh;
+	int vrefresh;
 	uint64_t rate[] = {0};
 	uint32_t step_size;
-	drmModeModeInfo virtual_mode;
+	int start, end, step;
+	drmModeModeInfo *virtual_mode = NULL;
+	bool need_low_rr = flags & TEST_SEAMLESS_VIRTUAL_RR_BOTTOM_UP;
 
-	igt_info("Use HIGH_RR Mode as default\n");
-	kmstest_dump_mode(&data->switch_modes[HIGH_RR_MODE]);
+	virtual_mode = get_selected_fixed_mode(output, need_low_rr);
+	if (!virtual_mode)
+		return;
+
+	igt_info("Use %s_RR Mode as default\n", need_low_rr ? "LOW" : "HIGH");
+	kmstest_dump_mode(virtual_mode);
 
 	prepare_test(data, output, crtc);
-	rate[0] = igt_kms_frame_time_from_vrefresh(data->switch_modes[HIGH_RR_MODE].vrefresh);
+	rate[0] = igt_kms_frame_time_from_vrefresh(virtual_mode->vrefresh);
 
 	/*
 	 * Sink with DRR and VRR can be in downclock mode so
-	 * switch to highest refresh rate mode.
+	 * switch to desired requested rate mode.
 	 */
-	igt_output_override_mode(output, &data->switch_modes[HIGH_RR_MODE]);
+	igt_output_override_mode(output, virtual_mode);
 	igt_assert(igt_display_try_commit_atomic(&data->display, DRM_MODE_PAGE_FLIP_EVENT, NULL) == 0);
 
 	result = flip_and_measure(data, output, rate, 1, TEST_DURATION_NS);
@@ -777,22 +830,29 @@ test_seamless_virtual_rr_basic(data_t *data, igt_crtc_t *crtc,
 		     "Refresh rate (%u Hz) %"PRIu64"ns: Target threshold not reached, result was %u%%\n",
 		     data->switch_modes[HIGH_RR_MODE].vrefresh, rate[0], result);
 
-	/*
-	 * Calculate step size by considering the no. of steps required to
-	 * reach Vmin to Vmax as 5.
-	 */
-	step_size = (data->range.max - data->range.min) / 5;
-
 	/* Switch to Virtual RR */
-	virtual_mode = *igt_output_get_mode(output);
+	virtual_mode = igt_output_get_mode(output);
+
+	if (flags & TEST_SEAMLESS_VIRTUAL_RR_TOP_DOWN) {
+		start = data->range.max;
+		end = data->range.min;
+		step = -1;
+	} else {
+		start = data->range.min;
+		end = data->range.max;
+		step = 1;
+	}
 
-	for (vrefresh = data->range.min + step_size; vrefresh < data->range.max; vrefresh += step_size) {
-		virtual_rr_vrr_range_mode(&virtual_mode, vrefresh);
+	for (vrefresh = start; (step > 0) ? (vrefresh <= end) : (vrefresh >= end); vrefresh += step) {
+		if (!virtual_rr_vrr_range_mode(data, virtual_mode, vrefresh))
+			continue;
 
 		igt_info("Requesting Virtual Mode with Refresh Rate (%u Hz): \n", vrefresh);
-		kmstest_dump_mode(&virtual_mode);
+		kmstest_dump_mode(virtual_mode);
 
-		igt_output_override_mode(output, &virtual_mode);
+		igt_output_override_mode(output, virtual_mode);
+
+		igt_assert(igt_display_try_commit_atomic(&data->display, DRM_MODE_ATOMIC_TEST_ONLY, NULL) == 0);
 		igt_assert(igt_display_try_commit_atomic(&data->display, 0, NULL) == 0);
 
 		rate[0] = igt_kms_frame_time_from_vrefresh(vrefresh);
@@ -1092,9 +1152,13 @@ int igt_main_args("drs:", long_opts, help_str, opt_handler, &data)
 		igt_subtest_with_dynamic("flip-basic-fastset")
 			run_vrr_test(&data, test_basic, TEST_FASTSET);
 
-		igt_describe("Test to switch to any custom virtual mode in VRR range without modeset.");
-		igt_subtest_with_dynamic("seamless-rr-switch-virtual")
-			run_vrr_test(&data, test_seamless_virtual_rr_basic, TEST_SEAMLESS_VIRTUAL_RR);
+		igt_describe("Test to switch to all virtual modes in VRR range without modeset.");
+		igt_subtest_with_dynamic("seamless-rr-switch-virtual-top-down")
+			run_vrr_test(&data, test_seamless_virtual_rr_basic, TEST_SEAMLESS_VIRTUAL_RR_TOP_DOWN);
+
+		igt_describe("Test to switch to all virtual modes in VRR range without modeset.");
+		igt_subtest_with_dynamic("seamless-rr-switch-virtual-bottom-up")
+			run_vrr_test(&data, test_seamless_virtual_rr_basic, TEST_SEAMLESS_VIRTUAL_RR_BOTTOM_UP);
 
 		igt_describe("Test to validate the link-off between active frames in "
 			     "non-PSR operation.");
-- 
2.34.1