Re: [PATCH i-g-t 6/6] tests/kms_pipe_crc_basic: Add MST suspend-resume test

["Joshi, Kunal1" <kunal1.joshi@intel.com>]

Hello Jani,

On 01-04-2026 17:22, Jani Nikula wrote:
> On Wed, 01 Apr 2026, Kunal Joshi <kunal1.joshi@intel.com> wrote:
>> Add a new subtest mst-suspend-read-crc that verifies MST outputs
>> preserve display content (via CRC comparison) across S3 suspend/resume.
>>
>> The test enumerates all connected DP MST topologies, and for each root
>> connector exercises all non-empty subsets of the discovered MST outputs.
>> For each subset it:
>>   - Assigns pipes and selects non-joiner modes
>>   - Fits modes within bandwidth constraints
>>   - Creates green FBs, commits, and collects pre-suspend CRCs
>>   - Suspends to memory and resumes
>>   - Collects post-suspend CRCs and asserts they match
> tests/kms_pipe_crc_basic.c is supposed to be the basic CRC test. Adding
> MST to it is fine, I guess, but adding all the Intel specific joiner
> stuff here seems questionable.
>
> IMO basically anything that needs to know anything about the concept of
> "pipes" (as opposed to CRTCs and CRTC indexes) should be inside
> tests/intel or minimized within checks for Intel devices.
>
>
> BR,
> Jani.
Agreed, Will add checks.

Thanks and Regards
Kunal Joshi
>
>> v2:
>> - Add error handling for igt_pipe_crc_new (Thasleem)
>> - Improve log format with index for clarity (Thasleem)
>> - Order declarations in decreasing line length (Thasleem)
>> - Add print message when no MST found (Thasleem)
>> - Add bounds check for idx in subset loop (Thasleem)
>> - Use igt_crtc_crc_new() instead of igt_pipe_crc_new() (Ville)
>>
>> v3:
>> - framebuffers missing in commit (Bilal)
>>
>> v4:
>> - Drop cleanup framework
>>
>> v5:
>> - Use igt_debug instead of igt_info for CRC logging (Thasleem)
>> - Remove  comments (Suraj)
>> - Remove double vblank waits before/after suspend (Suraj)
>> - Rename variable (Thasleem)
>> - Two-pass approach (Suraj)
>>
>> Signed-off-by: Kunal Joshi <kunal1.joshi@intel.com>
>> Reviewed-by: Mohammed Thasleem <mohammed.thasleem@intel.com>
>> ---
>>   tests/kms_pipe_crc_basic.c | 318 +++++++++++++++++++++++++++++++++++++
>>   tests/meson.build          |   3 +
>>   2 files changed, 321 insertions(+)
>>
>> diff --git a/tests/kms_pipe_crc_basic.c b/tests/kms_pipe_crc_basic.c
>> index 42e141545..d8369807e 100644
>> --- a/tests/kms_pipe_crc_basic.c
>> +++ b/tests/kms_pipe_crc_basic.c
>> @@ -32,7 +32,10 @@
>>   
>>   #include "igt.h"
>>   #include "igt_sysfs.h"
>> +#include "intel/kms_mst_helper.h"
>> +#include "intel/kms_joiner_helper.h"
>>   #include <errno.h>
>> +#include <limits.h>
>>   #include <stdbool.h>
>>   #include <stdio.h>
>>   #include <string.h>
>> @@ -77,6 +80,11 @@
>>    *              CRTC does not cause issues.
>>    */
>>   
>> +/**
>> + * SUBTEST: mst-suspend-read-crc
>> + * Description: MST suspend test for pipe CRC reads.
>> + */
>> +
>>   static bool extended;
>>   static int active_crtcs[IGT_MAX_PIPES];
>>   static uint32_t last_crtc_index;
>> @@ -96,6 +104,310 @@ static struct {
>>   	{ .r = 0.0, .g = 1.0, .b = 1.0 },
>>   };
>>   
>> +#define MAX_MST_OUTPUT	3
>> +
>> +struct mst_root_info {
>> +	int root_id;
>> +	igt_output_t *mst_outputs[IGT_MAX_PIPES];
>> +	int num_mst;
>> +};
>> +
>> +static void collect_single_crc(igt_crtc_t *crtc, igt_crc_t *crc)
>> +{
>> +	igt_pipe_crc_t *pipe_crc;
>> +
>> +	pipe_crc = igt_crtc_crc_new(crtc, IGT_PIPE_CRC_SOURCE_AUTO);
>> +	igt_assert(pipe_crc);
>> +	igt_pipe_crc_collect_crc(pipe_crc, crc);
>> +	igt_pipe_crc_free(pipe_crc);
>> +}
>> +
>> +static void collect_crc_for_active_outputs(igt_output_t **outputs,
>> +					   int num_outputs,
>> +					   igt_crc_t *crcs,
>> +					   bool post_suspend)
>> +{
>> +	int i;
>> +
>> +	for (i = 0; i < num_outputs; i++) {
>> +		igt_output_t *output = outputs[i];
>> +		igt_crtc_t *crtc = igt_output_get_driving_crtc(output);
>> +
>> +		if (post_suspend)
>> +			igt_require_f(crtc,
>> +				      "POST-SUSPEND: no driving CRTC for %s (topology changed?)\n",
>> +				      output->name);
>> +		else
>> +			igt_assert_f(crtc,
>> +				     "PRE-SUSPEND: no driving CRTC for %s (bad pipe assignment?)\n",
>> +				     output->name);
>> +
>> +		collect_single_crc(crtc, &crcs[i]);
>> +	}
>> +}
>> +
>> +static void wait_for_vblanks(igt_output_t **outputs, int num_outputs,
>> +			     bool post_suspend)
>> +{
>> +	int i;
>> +
>> +	for (i = 0; i < num_outputs; i++) {
>> +		igt_crtc_t *crtc = igt_output_get_driving_crtc(outputs[i]);
>> +
>> +		if (post_suspend)
>> +			igt_require_f(crtc,
>> +				      "POST-SUSPEND: no driving CRTC for %s during vblank wait (topology changed?)\n",
>> +				      outputs[i]->name);
>> +		else
>> +			igt_assert_f(crtc,
>> +				     "PRE-SUSPEND: no driving CRTC for %s during vblank wait (bad pipe assignment?)\n",
>> +				     outputs[i]->name);
>> +
>> +		igt_wait_for_vblank(crtc);
>> +	}
>> +}
>> +
>> +static void log_crc_for_outputs(igt_output_t **outputs, int num_outputs,
>> +				igt_crc_t *crcs, const char *stage)
>> +{
>> +	int i;
>> +
>> +	for (i = 0; i < num_outputs; i++) {
>> +		igt_output_t *o = outputs[i];
>> +		drmModeModeInfo *m = igt_output_get_mode(o);
>> +		char *s = igt_crc_to_string(&crcs[i]);
>> +		igt_crtc_t *crtc = igt_output_get_driving_crtc(o);
>> +
>> +		igt_debug("[%d] %s: output %s -> crtc %s, CRC %s, mode %dx%d@%d\n",
>> +			  i, stage, o->name,
>> +			  igt_crtc_name(crtc),
>> +			  s,
>> +			  m ? m->hdisplay : -1,
>> +			  m ? m->vdisplay : -1,
>> +			  m ? m->vrefresh : 0);
>> +		free(s);
>> +	}
>> +}
>> +
>> +static void select_non_joiner_modes(int drm_fd, igt_output_t **outputs,
>> +				    int num_outputs)
>> +{
>> +	int max_dotclock = igt_get_max_dotclock(drm_fd);
>> +	int i;
>> +
>> +	if (max_dotclock <= 0)
>> +		max_dotclock = INT_MAX;
>> +
>> +	for (i = 0; i < num_outputs; i++) {
>> +		igt_output_t *output = outputs[i];
>> +		drmModeModeInfo non_joiner_mode;
>> +
>> +		igt_require_f(max_non_joiner_mode_found(drm_fd,
>> +							output->config.connector,
>> +							max_dotclock,
>> +							&non_joiner_mode),
>> +			      "No non-joiner mode found for %s\n",
>> +			      output->name);
>> +		igt_output_override_mode(output, &non_joiner_mode);
>> +	}
>> +}
>> +
>> +static void create_fbs_for_outputs(int drm_fd, igt_output_t **outputs,
>> +				   int num_outputs, struct igt_fb *fbs)
>> +{
>> +	int i;
>> +
>> +	for (i = 0; i < num_outputs; i++) {
>> +		igt_output_t *output = outputs[i];
>> +		drmModeModeInfo *mode = igt_output_get_mode(output);
>> +		igt_plane_t *primary;
>> +
>> +		igt_require_f(mode, "No mode available for output %s\n", output->name);
>> +
>> +		primary = igt_output_get_plane_type(output, DRM_PLANE_TYPE_PRIMARY);
>> +
>> +		igt_create_color_fb(drm_fd,
>> +				    mode->hdisplay, mode->vdisplay,
>> +				    DRM_FORMAT_XRGB8888,
>> +				    DRM_FORMAT_MOD_LINEAR,
>> +				    0.0, 1.0, 0.0,
>> +				    &fbs[i]);
>> +		igt_plane_set_fb(primary, &fbs[i]);
>> +	}
>> +}
>> +
>> +static void run_mst_subset_and_verify(igt_display_t *display,
>> +				      igt_output_t **active_outputs,
>> +				      int num_active,
>> +				      int n_crtcs,
>> +				      uint32_t master_pipes_mask,
>> +				      uint32_t valid_pipes_mask)
>> +{
>> +	igt_crc_t pre_crcs[MAX_MST_OUTPUT];
>> +	igt_crc_t post_crcs[MAX_MST_OUTPUT];
>> +	struct igt_fb fbs[MAX_MST_OUTPUT];
>> +	uint32_t used_pipes_mask = 0;
>> +	enum igt_suspend_test stest = SUSPEND_TEST_NONE;
>> +	int drm_fd = display->drm_fd;
>> +	int i;
>> +
>> +	igt_require_f(num_active <= n_crtcs,
>> +		      "Not enough crtcs for MST subset\n");
>> +
>> +	igt_require(igt_assign_pipes_for_outputs(drm_fd,
>> +						 active_outputs,
>> +						 num_active,
>> +						 n_crtcs,
>> +						 &used_pipes_mask,
>> +						 master_pipes_mask,
>> +						 valid_pipes_mask));
>> +
>> +	select_non_joiner_modes(drm_fd, active_outputs, num_active);
>> +
>> +	igt_require_f(igt_fit_modes_in_bw(display),
>> +		      "Unable to fit modes in bw\n");
>> +
>> +	create_fbs_for_outputs(drm_fd, active_outputs, num_active, fbs);
>> +
>> +	igt_display_commit2(display, COMMIT_ATOMIC);
>> +
>> +	/* rtcwake cmd is not supported on MTK devices */
>> +	if (is_mtk_device(drm_fd))
>> +		stest = SUSPEND_TEST_DEVICES;
>> +
>> +	igt_info("MST subset: %d outputs, n_crtcs=%d\n",
>> +		 num_active, n_crtcs);
>> +
>> +	wait_for_vblanks(active_outputs, num_active, false);
>> +
>> +	collect_crc_for_active_outputs(active_outputs,
>> +				       num_active,
>> +				       pre_crcs, false);
>> +
>> +	log_crc_for_outputs(active_outputs, num_active, pre_crcs, "PRE-SUSPEND");
>> +
>> +	igt_system_suspend_autoresume(SUSPEND_STATE_MEM, stest);
>> +
>> +	wait_for_vblanks(active_outputs, num_active, true);
>> +
>> +	collect_crc_for_active_outputs(active_outputs,
>> +				       num_active,
>> +				       post_crcs, true);
>> +
>> +	log_crc_for_outputs(active_outputs, num_active, post_crcs, "POST-SUSPEND");
>> +
>> +	for (i = 0; i < num_active; i++)
>> +		igt_assert_crc_equal(&pre_crcs[i], &post_crcs[i]);
>> +
>> +	/* Detach FBs from planes and remove them to leave a clean state */
>> +	for (i = 0; i < num_active; i++) {
>> +		igt_plane_t *primary =
>> +			igt_output_get_plane_type(active_outputs[i],
>> +						  DRM_PLANE_TYPE_PRIMARY);
>> +		igt_plane_set_fb(primary, NULL);
>> +		igt_remove_fb(drm_fd, &fbs[i]);
>> +	}
>> +}
>> +
>> +static int discover_mst_roots(igt_display_t *display,
>> +			      struct mst_root_info *roots)
>> +{
>> +	igt_output_t *output;
>> +	int drm_fd = display->drm_fd;
>> +	int num_roots = 0;
>> +	int ret, i;
>> +
>> +	for_each_connected_output(display, output) {
>> +		bool root_seen = false;
>> +		int root_id;
>> +
>> +		root_id = igt_get_dp_mst_connector_id(output);
>> +		if (root_id < 0)
>> +			continue;
>> +
>> +		for (i = 0; i < num_roots; i++)
>> +			if (roots[i].root_id == root_id)
>> +				root_seen = true;
>> +
>> +		if (root_seen)
>> +			continue;
>> +
>> +		if (num_roots >= IGT_MAX_PIPES)
>> +			break;
>> +
>> +		roots[num_roots].root_id = root_id;
>> +		roots[num_roots].num_mst = 0;
>> +		ret = igt_find_all_mst_output_in_topology(drm_fd,
>> +							  display, output,
>> +							  roots[num_roots].mst_outputs,
>> +							  &roots[num_roots].num_mst);
>> +		igt_require(ret == 0);
>> +
>> +		if (roots[num_roots].num_mst == 0)
>> +			continue;
>> +
>> +		if (roots[num_roots].num_mst > MAX_MST_OUTPUT)
>> +			roots[num_roots].num_mst = MAX_MST_OUTPUT;
>> +
>> +		num_roots++;
>> +	}
>> +
>> +	return num_roots;
>> +}
>> +
>> +static void mst_suspend_read_crc(igt_display_t *display)
>> +{
>> +	struct mst_root_info roots[IGT_MAX_PIPES];
>> +	igt_output_t *active_outputs[MAX_MST_OUTPUT];
>> +	uint32_t valid_pipes_mask = 0;
>> +	uint32_t master_pipes_mask;
>> +	int n_crtcs = igt_display_n_crtcs(display);
>> +	int num_roots, num_active, i;
>> +	igt_crtc_t *crtc;
>> +
>> +	for_each_crtc(display, crtc)
>> +		valid_pipes_mask |= BIT(crtc->pipe);
>> +
>> +	igt_set_all_master_pipes_for_platform(display, &master_pipes_mask);
>> +
>> +	num_roots = discover_mst_roots(display, roots);
>> +	igt_require_f(num_roots > 0, "No MST roots found\n");
>> +
>> +	for (i = 0; i < num_roots; i++) {
>> +		igt_dynamic_f("mst-root-%d", roots[i].root_id) {
>> +			int mask;
>> +
>> +			for (mask = 1; mask < (1 << roots[i].num_mst); mask++) {
>> +				int bit, idx = 0;
>> +
>> +				for (bit = 0; bit < roots[i].num_mst; bit++) {
>> +					if (!(mask & (1 << bit)))
>> +						continue;
>> +
>> +					if (idx >= MAX_MST_OUTPUT)
>> +						break;
>> +
>> +					active_outputs[idx++] =
>> +						roots[i].mst_outputs[bit];
>> +				}
>> +
>> +				num_active = idx;
>> +				if (!num_active)
>> +					continue;
>> +
>> +				igt_display_reset(display);
>> +
>> +				run_mst_subset_and_verify(display,
>> +							  active_outputs,
>> +							  num_active,
>> +							  n_crtcs,
>> +							  master_pipes_mask,
>> +							  valid_pipes_mask);
>> +			}
>> +		}
>> +	}
>> +}
>> +
>>   static bool simulation_constraint(igt_crtc_t *crtc)
>>   {
>>   	if (igt_run_in_simulation() && !extended &&
>> @@ -525,6 +837,12 @@ int igt_main_args("e", NULL, help_str, opt_handler, NULL)
>>   		}
>>   	}
>>   
>> +	igt_describe("MST suspend test for pipe CRC reads.");
>> +	igt_subtest_with_dynamic("mst-suspend-read-crc") {
>> +		igt_require(igt_display_has_mst_output(&data.display));
>> +		mst_suspend_read_crc(&data.display);
>> +	}
>> +
>>   	igt_fixture() {
>>   		igt_display_fini(&data.display);
>>   		drm_close_driver(data.drm_fd);
>> diff --git a/tests/meson.build b/tests/meson.build
>> index cecb4a8ae..a1e42755e 100644
>> --- a/tests/meson.build
>> +++ b/tests/meson.build
>> @@ -402,6 +402,9 @@ extra_sources = {
>>              join_paths ('intel', 'kms_joiner_helper.c') ],
>>   	'kms_dsc': [ join_paths ('intel', 'kms_dsc_helper.c') ],
>>   	'kms_joiner': [ join_paths ('intel', 'kms_joiner_helper.c') ],
>> +	'kms_pipe_crc_basic': [
>> +           join_paths ('intel', 'kms_mst_helper.c'),
>> +           join_paths ('intel', 'kms_joiner_helper.c') ],
>>   	'kms_psr2_sf':  [ join_paths ('intel', 'kms_dsc_helper.c') ],
>>   }