[PATCH i-g-t 2/3] tests/intel/kms_dp_linktrain_fallback: add dsc-fallback test

Sharma, Swati2 swati2.sharma at intel.com
Mon Jan 27 09:17:01 UTC 2025


Hi Kunal,

Please have consistency in subject of your patches.
Either start subject with capital letter or small letter.

Also, please update igt_test_description()

On 27-01-2025 11:59 am, Kunal Joshi wrote:
> add new dsc-fallback test which finds a mode
%s add/Add
> which can be driven without DSC at current link
> params and reduces link param till we have
> combination (link_rate, lane_count) which requires
> DSC to be enabled.
>
> Cc: Ankit Nautiyal <ankit.k.nautiyal at intel.com>
> Signed-off-by: Kunal Joshi <kunal1.joshi at intel.com>
> ---
>   tests/intel/kms_dp_linktrain_fallback.c | 352 +++++++++++++++++++++---
>   tests/meson.build                       |   4 +-
>   2 files changed, 311 insertions(+), 45 deletions(-)
>
> diff --git a/tests/intel/kms_dp_linktrain_fallback.c b/tests/intel/kms_dp_linktrain_fallback.c
> index b10946781..471381f1d 100644
> --- a/tests/intel/kms_dp_linktrain_fallback.c
> +++ b/tests/intel/kms_dp_linktrain_fallback.c
> @@ -17,10 +17,14 @@
>   
>   #include "igt.h"
>   #include "kms_mst_helper.h"
> +#include "kms_dsc_helper.h"
>   
>   /**
>    * SUBTEST: dp-fallback
>    * Description: Test fallback on DP connectors
> + *
> + * SUBTEST: dsc-fallback
> + * Description: Test we fallback to DSC when BW isn't sufficient
Remove "we"
>    */
>   
>   #define RETRAIN_COUNT 1
> @@ -238,16 +242,124 @@ static int check_condition_with_timeout(int drm_fd, igt_output_t *output,
>   	}
>   }
>   
> +/*
> + * Force a link training failure followed by link retrain, then
> + * block until the driver has no further pending retrain/failure.
> + * Returns false if we time out waiting.
> + */
> +static bool force_failure_and_wait(data_t *data,
> +				   igt_output_t *output,
> +				   int failure_type,
> +				   int retrain_count,
> +				   double interval,
> +				   double timeout)
> +{
> +	igt_force_lt_failure(data->drm_fd, output, failure_type);
> +	igt_force_link_retrain(data->drm_fd, output, retrain_count);
> +
> +	/* Wait until there's no pending retrain */
> +	if (check_condition_with_timeout(data->drm_fd, output,
> +					 igt_get_dp_pending_retrain,
> +					 interval, timeout)) {
> +		igt_info("Timed out waiting for pending retrain.\n");
> +		return false;
> +	}
> +
> +	/* Wait until there's no pending LT failures */
> +	if (check_condition_with_timeout(data->drm_fd, output,
> +					 igt_get_dp_pending_lt_failures,
> +					 interval, timeout)) {
> +		igt_info("Timed out waiting for pending LT failures.\n");
> +		return false;
> +	}
> +
> +	return true;
> +}
> +
> +/*
> + * Waits for a hotplug event, then checks that the link-status is BAD.
> + * Returns false if the link-status isn't BAD or no hotplug arrives in time.
> + */
> +static bool wait_for_hotplug_and_check_bad(int drm_fd,
> +					   data_t *data,
> +					   igt_output_t *output,
> +					   struct udev_monitor *mon,
> +					   double hotplug_timeout)
> +{
> +	uint32_t link_status_prop_id;
> +	uint64_t link_status_value;
> +	drmModePropertyPtr link_status_prop;
> +
> +	if (!igt_hotplug_detected(mon, hotplug_timeout)) {
> +		igt_info("No hotplug event within %.2f seconds.\n", hotplug_timeout);
> +		return false;
> +	}
> +
> +	kmstest_get_property(drm_fd,
> +			     output->config.connector->connector_id,
> +			     DRM_MODE_OBJECT_CONNECTOR,
> +			     "link-status",
> +			     &link_status_prop_id, &link_status_value,
> +			     &link_status_prop);
> +
> +	if (link_status_value != DRM_MODE_LINK_STATUS_BAD) {
> +		igt_info("Expected link-status=BAD but got %" PRIu64 "\n",
> +			 link_status_value);
> +		return false;
> +	}
> +
> +	return true;
> +}
> +
> +/*
> + * Sets link status=GOOD for the specified outputs, then calls
> + * validate_modeset_for_outputs() to re-commit. Returns false
> + * if the re-commit fails.
> + */
> +static bool fix_link_status_and_recommit(data_t *data,
> +					 igt_output_t *outputs[],
> +					 int *output_count,
> +					 drmModeModeInfo * modes[],
> +					 struct igt_fb fbs[],
> +					 struct igt_plane *primarys[])
> +{
> +	int i;
> +	igt_output_t *out;
> +
> +	/* Set link-status=GOOD on each tested output */
> +	for_each_connected_output(&data->display, out) {
> +		for (i = 0; i < *output_count; i++) {
> +			if (out->id == outputs[i]->id) {
> +				igt_output_set_prop_value(
> +					out, IGT_CONNECTOR_LINK_STATUS,
> +					DRM_MODE_LINK_STATUS_GOOD);
> +			}
> +		}
> +	}
> +
> +	if (!validate_modeset_for_outputs(data, outputs, output_count,
> +					  modes, fbs, primarys)) {
> +		igt_info("Modeset validation failed after forcing link-status=GOOD.\n");
> +		return false;
> +	}
> +
> +	if (igt_display_try_commit_atomic(&data->display,
> +					  DRM_MODE_ATOMIC_ALLOW_MODESET,
> +					  NULL) != 0) {
> +		igt_info("Commit failed after restoring link-status=GOOD.\n");
> +		return false;
> +	}
> +
> +	return true;
> +}
> +
>   static void test_fallback(data_t *data, bool is_mst)
>   {
>   	int output_count, retries;
>   	int max_link_rate, curr_link_rate, prev_link_rate;
>   	int max_lane_count, curr_lane_count, prev_lane_count;
>   	igt_output_t *outputs[IGT_MAX_PIPES];
> -	uint32_t link_status_prop_id;
> -	uint64_t link_status_value;
> -	drmModeModeInfo *modes[IGT_MAX_PIPES];
> -	drmModePropertyPtr link_status_prop;
> +	drmModeModeInfo * modes[IGT_MAX_PIPES];
>   	struct igt_fb fbs[IGT_MAX_PIPES];
>   	struct igt_plane *primarys[IGT_MAX_PIPES];
>   	struct udev_monitor *mon;
> @@ -256,71 +368,71 @@ static void test_fallback(data_t *data, bool is_mst)
>   
>   	igt_display_reset(&data->display);
>   	igt_reset_link_params(data->drm_fd, data->output);
> -	if (!setup_outputs(data, is_mst, outputs,
> -			   &output_count, modes, fbs,
> -			   primarys))
> +	igt_force_link_retrain(data->drm_fd, data->output, 1);
> +
> +	if (!setup_outputs(data, is_mst, outputs, &output_count,
> +			   modes, fbs, primarys))
>   		return;
>   
>   	igt_info("Testing link training fallback on %s\n",
>   		 igt_output_name(data->output));
>   	max_link_rate = igt_get_max_link_rate(data->drm_fd, data->output);
>   	max_lane_count = igt_get_max_lane_count(data->drm_fd, data->output);
> +
>   	prev_link_rate = igt_get_current_link_rate(data->drm_fd, data->output);
>   	prev_lane_count = igt_get_current_lane_count(data->drm_fd, data->output);
>   
> -	while (!igt_get_dp_link_retrain_disabled(data->drm_fd,
> -						 data->output)) {
> +	while (!igt_get_dp_link_retrain_disabled(data->drm_fd, data->output)) {
>   		igt_info("Current link rate: %d, Current lane count: %d\n",
> -			 prev_link_rate,
> -			 prev_lane_count);
> +			 prev_link_rate, prev_lane_count);
> +
>   		mon = igt_watch_uevents();
> -		igt_force_lt_failure(data->drm_fd, data->output,
> -				     LT_FAILURE_REDUCED_CAPS);
> -		igt_force_link_retrain(data->drm_fd, data->output,
> -				       RETRAIN_COUNT);
> -
> -		igt_assert_eq(check_condition_with_timeout(data->drm_fd,
> -							   data->output,
> -							   igt_get_dp_pending_retrain,
> -							   1.0, 20.0), 0);
> -		igt_assert_eq(check_condition_with_timeout(data->drm_fd,
> -							   data->output,
> -							   igt_get_dp_pending_lt_failures,
> -							   1.0, 20.0), 0);
> +
> +		/* Force link failure, wait for retrain to clear */
> +		igt_assert_f(force_failure_and_wait(data, data->output,
> +						    LT_FAILURE_REDUCED_CAPS,
> +						    RETRAIN_COUNT,
> +						    1.0, 20.0),
> +			     "Link training failure steps timed out\n");
>   
>   		if (igt_get_dp_link_retrain_disabled(data->drm_fd,
>   						     data->output)) {
>   			igt_reset_connectors();
> +			igt_flush_uevents(mon);
>   			return;
>   		}
>   
> -		igt_assert_f(igt_hotplug_detected(mon, 20),
> -			     "Didn't get hotplug for force link training failure\n");
> -
> -		kmstest_get_property(data->drm_fd,
> -				data->output->config.connector->connector_id,
> -				DRM_MODE_OBJECT_CONNECTOR, "link-status",
> -				&link_status_prop_id, &link_status_value,
> -				&link_status_prop);
> -		igt_assert_eq(link_status_value, DRM_MODE_LINK_STATUS_BAD);
> +		/* Wait for hotplug + check link-status=BAD */
> +		igt_assert_f(wait_for_hotplug_and_check_bad(data->drm_fd,
> +							    data,
> +							    data->output,
> +							    mon,
> +							    20.0),
> +			     "Didn't get hotplug or link-status=BAD\n");
>   		igt_flush_uevents(mon);
> -		set_connector_link_status_good(data, outputs, &output_count);
> -		igt_assert_f(validate_modeset_for_outputs(data,
> +
> +		/* Set link-status=GOOD and re-commit */
> +		igt_assert_f(fix_link_status_and_recommit(data,
>   							  outputs,
>   							  &output_count,
>   							  modes,
>   							  fbs,
>   							  primarys),
>   			     "modeset failed\n");
> -		igt_display_commit2(&data->display, COMMIT_ATOMIC);
>   
> -		igt_assert_eq(data->output->values[IGT_CONNECTOR_LINK_STATUS], DRM_MODE_LINK_STATUS_GOOD);
> -		curr_link_rate = igt_get_current_link_rate(data->drm_fd, data->output);
> -		curr_lane_count = igt_get_current_lane_count(data->drm_fd, data->output);
> +		/* Ensure link-status is GOOD again */
> +		igt_assert_eq(data->output->values[IGT_CONNECTOR_LINK_STATUS],
> +			      DRM_MODE_LINK_STATUS_GOOD);
> +
> +		curr_link_rate = igt_get_current_link_rate(data->drm_fd,
> +							   data->output);
> +		curr_lane_count = igt_get_current_lane_count(data->drm_fd,
> +							     data->output);
>   
>   		igt_assert_f((curr_link_rate < prev_link_rate ||
> -			     curr_lane_count < prev_lane_count) ||
> -			     ((curr_link_rate == max_link_rate && curr_lane_count == max_lane_count) && --retries),
> +			      curr_lane_count < prev_lane_count) ||
> +			     ((curr_link_rate == max_link_rate &&
> +			       curr_lane_count == max_lane_count) && --retries),
>   			     "Fallback unsuccessful\n");
>   
>   		prev_link_rate = curr_link_rate;
> @@ -328,7 +440,117 @@ static void test_fallback(data_t *data, bool is_mst)
>   	}
>   }
>   
> -static bool run_test(data_t *data)
> +static void test_dsc_sst_fallback(data_t *data)
> +{
> +	bool non_dsc_mode_found = false;
> +	bool dsc_fallback_successful = false;
> +	int ret;
> +	struct udev_monitor *mon;
> +	drmModeModeInfo *mode_to_check;
> +	igt_output_t *outputs[IGT_MAX_PIPES];
> +	int output_count = 0;
> +
> +	igt_info("Checking DSC fallback on %s\n", igt_output_name(data->output));
> +	data->pipe = PIPE_A;
> +
> +        igt_display_reset(&data->display);
> +        igt_reset_link_params(data->drm_fd, data->output);
Fix indentation here.
> +	igt_force_link_retrain(data->drm_fd, data->output, 1);
> +
> +	/* Find a mode that doesn't require DSC initially */
> +	for_each_connector_mode(data->output) {
> +		data->mode = &data->output->config.connector->modes[j__];
> +		igt_create_color_fb(data->drm_fd, data->mode->hdisplay,
> +				    data->mode->vdisplay, DRM_FORMAT_XRGB8888,
> +				    DRM_FORMAT_MOD_LINEAR, 0.0, 1.0, 0.0,
> +				    &data->fb);
> +		igt_output_override_mode(data->output, data->mode);
> +		igt_output_set_pipe(data->output, data->pipe);
> +		data->primary = igt_output_get_plane_type(data->output,
> +						DRM_PLANE_TYPE_PRIMARY);
> +		igt_plane_set_fb(data->primary, &data->fb);
> +
> +		ret = igt_display_try_commit_atomic(&data->display,
> +						    DRM_MODE_ATOMIC_TEST_ONLY |
> +						    DRM_MODE_ATOMIC_ALLOW_MODESET,
> +						    NULL);
> +		if (ret != 0) {
> +			igt_info("Skipping mode %dx%d@%d on %s\n",
> +				 data->mode->hdisplay, data->mode->vdisplay,
> +				 data->mode->vrefresh,
> +				 igt_output_name(data->output));
> +			continue;
> +		}
> +		igt_display_commit2(&data->display, COMMIT_ATOMIC);
> +
> +		if (!igt_is_dsc_enabled(data->drm_fd,
> +					data->output->name)) {
> +			drmModeModeInfo *non_dsc_mode
> +				= igt_output_get_mode(data->output);
> +			igt_info("Found mode %dx%d@%d %s that doesn't need DSC with link rate %d and lane count %d\n",
> +				 non_dsc_mode->hdisplay, non_dsc_mode->vdisplay,
> +				 non_dsc_mode->vrefresh, non_dsc_mode->name,
> +				 igt_get_current_link_rate(data->drm_fd, data->output),
> +				 igt_get_current_lane_count(data->drm_fd, data->output));
> +			non_dsc_mode_found = true;
> +			break;
> +		}
> +	}
> +	igt_require_f(non_dsc_mode_found,
> +		      "No non-DSC mode found on %s\n",
> +		      igt_output_name(data->output));
> +
> +
Remove extra new line
> +	/* Repeatedly force link failure until DSC is required (or link is disabled) */
> +	while (!igt_get_dp_link_retrain_disabled(data->drm_fd, data->output)) {
> +		mon = igt_watch_uevents();
> +
> +		igt_assert_f(force_failure_and_wait(data, data->output,
> +						    LT_FAILURE_REDUCED_CAPS,
> +						    RETRAIN_COUNT, 1.0, 20.0),
> +			     "Forcing DSC fallback timed out\n");
> +
> +		if (igt_get_dp_link_retrain_disabled(data->drm_fd,
> +						     data->output)) {
> +			igt_reset_connectors();
> +			igt_flush_uevents(mon);
> +			return;
> +		}
> +
> +		igt_assert_f(wait_for_hotplug_and_check_bad(data->drm_fd,
> +							    data,
> +							    data->output,
> +							    mon,
> +							    20.0),
> +			     "Didn't get hotplug or link-status=BAD for DSC\n");
> +		igt_flush_uevents(mon);
> +
> +		outputs[output_count++] = data->output;
> +		set_connector_link_status_good(data, outputs, &output_count);
> +		igt_display_commit2(&data->display, COMMIT_ATOMIC);
> +
> +		mode_to_check = igt_output_get_mode(data->output);
> +
> +		if (igt_is_dsc_enabled(data->drm_fd, data->output->name)) {
> +			igt_info("mode %dx%d@%d now requires DSC with link rate %d and lane count %d\n",
> +				 mode_to_check->hdisplay, mode_to_check->vdisplay,
> +				 mode_to_check->vrefresh,
> +				 igt_get_current_link_rate(data->drm_fd, data->output),
> +				 igt_get_current_lane_count(data->drm_fd, data->output));
> +			igt_info("DSC fallback successful on %s\n",
> +				 igt_output_name(data->output));
> +			dsc_fallback_successful = true;
> +			break;
> +		} else {
> +			igt_info("mode %dx%d@%d still doesn't require DSC\n",
> +				 mode_to_check->hdisplay, mode_to_check->vdisplay,
> +				 mode_to_check->vrefresh);
> +		}
> +	}
> +	igt_assert_f(dsc_fallback_successful, "DSC fallback unsuccessful\n");
> +}
> +
> +static bool run_lt_fallback_test(data_t *data)
>   {
>   	bool ran = false;
>   	igt_output_t *output;
> @@ -366,6 +588,43 @@ static bool run_test(data_t *data)
>   	return ran;
>   }
>   
> +static bool run_dsc_sst_fallaback_test(data_t *data)
> +{
> +	bool ran = false;
> +	igt_output_t *output;
> +
> +	if (!is_dsc_supported_by_source(data->drm_fd)) {
> +		igt_info("DSC not supported by source.\n");
> +		return ran;
> +	}
> +
> +	for_each_connected_output(&data->display, output) {
> +		data->output = output;
> +
> +		if (!igt_has_force_link_training_failure_debugfs(data->drm_fd,
> +								 data->output)) {
> +			igt_info("Output %s doesn't support forcing link training.\n",
> +				 igt_output_name(data->output));
> +			continue;
> +		}
> +
> +		if (output->config.connector->connector_type != DRM_MODE_CONNECTOR_DisplayPort) {
> +			igt_info("Skipping output %s as it's not DP\n", output->name);
> +			continue;
> +		}
> +
> +		if (!is_dsc_supported_by_sink(data->drm_fd, data->output)) {
> +			igt_info("Skipping output %s as DSC not supported by sink\n",
> +				 igt_output_name(data->output));
> +			continue;
> +		}
> +
> +		ran = true;
> +		test_dsc_sst_fallback(data);
> +	}
> +	return ran;
> +}
> +
>   igt_main
>   {
>   	data_t data = {};
> @@ -381,8 +640,13 @@ igt_main
>   	}
>   
>   	igt_subtest("dp-fallback") {
> -		igt_require_f(run_test(&data),
> -			      "Skipping test as no output found or none supports fallback\n");
> +		igt_require_f(run_lt_fallback_test(&data),
> +			      "Skipping test as no DP output found or none supports forcing link fail\n");
This rename and update of skip message should have been a separate patch.
> +	}
> +
> +	igt_subtest("dsc-fallback") {
> +		igt_require_f(run_dsc_sst_fallaback_test(&data),
> +			      "Skipping test: DSC fallback conditions not met.\n");
This should be in this patch only.
>   	}
>   
>   	igt_fixture {
> diff --git a/tests/meson.build b/tests/meson.build
> index 2cbd21c2a..dd75976dd 100644
> --- a/tests/meson.build
> +++ b/tests/meson.build
> @@ -367,7 +367,9 @@ extra_sources = {
>   	'kms_chamelium_frames': [ join_paths ('chamelium', 'kms_chamelium_helper.c') ],
>   	'kms_chamelium_hpd': [ join_paths ('chamelium', 'kms_chamelium_helper.c') ],
>   	'kms_dsc': [ join_paths ('intel', 'kms_dsc_helper.c') ],
> -	'kms_dp_linktrain_fallback': [join_paths ('intel', 'kms_mst_helper.c')],
> +	'kms_dp_linktrain_fallback': [
> +           join_paths ('intel', 'kms_mst_helper.c'),
> +           join_paths ('intel', 'kms_dsc_helper.c')],
>   	'kms_psr2_sf':  [ join_paths ('intel', 'kms_dsc_helper.c') ],
>   }
>   


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