Re: [PATCH i-g-t,v7 4/5] tests/intel/kms_dsc_helper: Add helper func()

[Karthik B S <karthik.b.s@intel.com>]

Hi Swati,

On 5/31/2026 1:06 AM, Swati Sharma wrote:
> Introduce check_dsc_joiner_constraints() to validate minimum pipe
> count, consecutive HW pipe availability, DSC slice requirements, and
> joiner support for DSC joiner scenarios.
>
> Update meson.build to link kms_joiner_helper.c into DSC-related
> tests so the new helper can call igt_is_joiner_supported_by_source().
>
> v2: -Avoid hardcoding min_pipes/min_slices, use enum values (Santhosh)
> v3: -Handle JOINED_PIPES_NONE/DEFAULT explicitly, return true (Karthik)
>      -Fix indentation/style issues (Karthik)
> v4: -Move consecutive pipe check (igt_crtc_for_pipe) into helper
>       rather than having it in the test (Karthik)
>
> Co-developed-by: Claude Opus 4.6
> Signed-off-by: Swati Sharma <swati2.sharma@intel.com>
> ---
>   tests/intel/kms_dsc_helper.c | 67 ++++++++++++++++++++++++++++++++++++
>   tests/intel/kms_dsc_helper.h |  5 +++
>   tests/meson.build            | 17 +++++----
>   3 files changed, 83 insertions(+), 6 deletions(-)
>
> diff --git a/tests/intel/kms_dsc_helper.c b/tests/intel/kms_dsc_helper.c
> index 29b998c2f..7856e33ef 100644
> --- a/tests/intel/kms_dsc_helper.c
> +++ b/tests/intel/kms_dsc_helper.c
> @@ -203,3 +203,70 @@ bool is_dsc_fractional_bpp_supported(int disp_ver, int drmfd, igt_output_t *outp
>   
>   	return true;
>   }
> +
Please add a description as to what constraints are being checked here?
> +bool check_dsc_joiner_constraints(int drm_fd,
> +				  igt_output_t *output,
> +				  igt_display_t *display,
> +				  enum pipe pipe,
> +				  int num_pipes,
> +				  enum joined_pipes type)
> +{
> +	int min_pipes = 0, min_slices = 0;
> +
> +	if (!igt_is_joiner_supported_by_source(drm_fd, type))
> +		return false;
> +
> +	/*
> +	 * For joiner, 2 slices per pipe is used
> +	 * i.e. min_slices = 2 * min_pipes
> +	 */
> +	switch (type) {
> +	case JOINED_PIPES_BIG_JOINER:
> +		min_pipes = JOINED_PIPES_BIG_JOINER;
> +		min_slices = min_pipes * 2;
> +		break;
> +	case JOINED_PIPES_ULTRA_JOINER:
> +		min_pipes = JOINED_PIPES_ULTRA_JOINER;
> +		min_slices = min_pipes * 2;
> +		break;
> +	case JOINED_PIPES_NONE:
> +	case JOINED_PIPES_DEFAULT:
> +		return true;
> +	default:
> +		igt_info("Unknown joiner type: %d\n", type);
> +		return false;
> +	}
> +
> +	if (num_pipes < min_pipes) {
> +		igt_info("%s requires minimum %d pipes\n",
> +			 igt_get_joined_pipes_name(type), min_pipes);
> +		return false;
> +	}
> +
> +	/* Verify consecutive HW pipes are available from this pipe */
> +	if (type == JOINED_PIPES_BIG_JOINER &&
> +	    !igt_crtc_for_pipe(display, pipe + 1))
> +		return false;
> +
> +	if (type == JOINED_PIPES_ULTRA_JOINER &&
> +	    (!igt_crtc_for_pipe(display, pipe + 1) ||
> +	     !igt_crtc_for_pipe(display, pipe + 2) ||
> +	     !igt_crtc_for_pipe(display, pipe + 3)))
> +		return false;
> +
> +	if (igt_get_dsc_sink_max_slice_count(drm_fd, output->name) < min_slices) {
> +		igt_info("Output %s doesn't support minimum %d slice count for %s\n",
> +			 igt_output_name(output), min_slices,
> +			 igt_get_joined_pipes_name(type));
> +		return false;
> +	}
> +
> +	if (!igt_has_force_joiner_debugfs(drm_fd, output->name)) {
> +		igt_info("Output %s doesn't support force_joiner debugfs for %s\n",
> +			 igt_output_name(output),
> +			 igt_get_joined_pipes_name(type));
> +		return false;

Is this check required inside the helper? Is the test fully blocked 
without force_joiner_debugfs?

Regards,
Karthik.B.S
> +	}
> +
> +	return true;
> +}
> diff --git a/tests/intel/kms_dsc_helper.h b/tests/intel/kms_dsc_helper.h
> index ee419c849..542fe46de 100644
> --- a/tests/intel/kms_dsc_helper.h
> +++ b/tests/intel/kms_dsc_helper.h
> @@ -8,6 +8,7 @@
>   
>   #include "igt.h"
>   #include "igt_sysfs.h"
> +#include "kms_joiner_helper.h"
>   #include <errno.h>
>   #include <getopt.h>
>   #include <math.h>
> @@ -39,5 +40,9 @@ void force_dsc_fractional_bpp_enable(int drmfd, igt_output_t *output);
>   void save_force_dsc_fractional_bpp_en(int drmfd, igt_output_t *output);
>   void restore_force_dsc_fractional_bpp_en(void);
>   bool is_dsc_fractional_bpp_supported(int disp_ver, int drmfd, igt_output_t *output);
> +bool check_dsc_joiner_constraints(int drm_fd, igt_output_t *output,
> +				  igt_display_t *display, enum pipe pipe,
> +				  int num_pipes,
> +				  enum joined_pipes type);
>   
>   #endif
> diff --git a/tests/meson.build b/tests/meson.build
> index fe0818118..3255e9282 100644
> --- a/tests/meson.build
> +++ b/tests/meson.build
> @@ -399,14 +399,19 @@ extra_sources = {
>   	'kms_chamelium_hpd': [ join_paths ('chamelium', 'kms_chamelium_helper.c') ],
>   	'kms_chamelium_sharpness_filter': [ join_paths ('chamelium', 'kms_chamelium_helper.c') ],
>   	'kms_dp_linktrain_fallback': [
> -           join_paths ('intel', 'kms_mst_helper.c'),
> -           join_paths ('intel', 'kms_dsc_helper.c') ],
> +          join_paths ('intel', 'kms_mst_helper.c'),
> +          join_paths ('intel', 'kms_dsc_helper.c'),
> +          join_paths ('intel', 'kms_joiner_helper.c') ],
>   	'kms_dp_link_training': [
> -           join_paths ('intel', 'kms_mst_helper.c'),
> -           join_paths ('intel', 'kms_joiner_helper.c') ],
> -	'kms_dsc': [ join_paths ('intel', 'kms_dsc_helper.c') ],
> +          join_paths ('intel', 'kms_mst_helper.c'),
> +          join_paths ('intel', 'kms_joiner_helper.c') ],
> +	'kms_dsc': [
> +          join_paths ('intel', 'kms_dsc_helper.c'),
> +          join_paths ('intel', 'kms_joiner_helper.c') ],
>   	'kms_joiner': [ join_paths ('intel', 'kms_joiner_helper.c') ],
> -	'kms_psr2_sf':  [ join_paths ('intel', 'kms_dsc_helper.c') ],
> +	'kms_psr2_sf': [
> +          join_paths ('intel', 'kms_dsc_helper.c'),
> +          join_paths ('intel', 'kms_joiner_helper.c') ],
>   }
>   
>   # Extra dependencies used on core and Intel drivers