Re: [PATCH i-g-t v3 04/11] tests/intel/kms_frontbuffer_tracking: consolidate fbc tests skip checks

["Reddy Guddati, Santhosh" <santhosh.reddy.guddati@intel.com>]

Hi Vinod,

On 16-04-2026 14:55, Vinod Govindapillai wrote:
> While looking for "no fbc reasons" and decide whether to skip any specific
> fbc related test, read the debugfs fbc status only once and look for any
> skip reasons. Move this as a library function so that other FBC specific
> tests could use the same library and all the skips reasons can be
> maintained in a single place.
> 
> Suggested-by: Jani Nikula <jani.nikula@intel.com>
> Signed-off-by: Vinod Govindapillai <vinod.govindapillai@intel.com>
> ---
>   lib/i915/intel_fbc.c                   | 37 +++++++++++++++
>   lib/i915/intel_fbc.h                   |  1 +
>   tests/intel/kms_frontbuffer_tracking.c | 63 ++++----------------------
>   3 files changed, 47 insertions(+), 54 deletions(-)
> 
> diff --git a/lib/i915/intel_fbc.c b/lib/i915/intel_fbc.c
> index 47f0e2fc1..e2fbe3680 100644
> --- a/lib/i915/intel_fbc.c
> +++ b/lib/i915/intel_fbc.c
> @@ -63,6 +63,43 @@ void intel_fbc_get_fbc_status(igt_crtc_t *crtc, char *fbc_status, int buf_size)
>   					    buf_size);
>   }
>   
> +/**
> + * intel_fbc_found_skip_reason
> + * @device: fd of the device
> + * @crtc_index: crtc index
> + *
> + * Read the debugfs entry for current fbc status of a crtc and check for any reasons
> + * why FBC cannot be enabled. This helps in skipping FBC test cases where FBC cannot
> + * be enabled. These no fbc reasons are defined by the driver.
> + *
> + * Returns:
> + * True if there is a reason that FBC cannot be enabled otherwise false.
> + */
> +bool intel_fbc_found_skip_reason(int device, int crtc_index)
> +{
> +	const char *const no_fbc_reasons[] = {
> +		"FBC disabled: not enough stolen memory",
> +		"FBC disabled: stride not supported",
> +		"FBC disabled: plane size too big",
> +		"FBC disabled: surface size too big",
> +		"FBC disabled: PSR1 enabled (Wa_14016291713)"
> +	};
> +	bool found_reason = false;
> +	char fbc_status[FBC_STATUS_BUF_LEN];
> +	int i;
> +
> +	intel_fbc_get_fbc_status_crtc_index(device, crtc_index, fbc_status,
> +					    sizeof(fbc_status));
> +
> +	if (strstr(fbc_status, "FBC Enabled\n"))

This should be "FBC enabled" as debugfs reports it as "enabled".

> +		return false;
> +
> +	for (i = 0; !found_reason && i < ARRAY_SIZE(no_fbc_reasons); i++)
> +		found_reason = strstr(fbc_status, no_fbc_reasons[i]);
> +
> +	return found_reason;
> +}
> +
>   /**
>    * intel_fbc_supported:
>    * @crtc: CRTC
> diff --git a/lib/i915/intel_fbc.h b/lib/i915/intel_fbc.h
> index f8a506f23..e4b9e5529 100644
> --- a/lib/i915/intel_fbc.h
> +++ b/lib/i915/intel_fbc.h
> @@ -20,5 +20,6 @@ bool intel_fbc_supported_for_psr_mode(igt_display_t *display, enum psr_mode mode
>   void intel_fbc_get_fbc_status_crtc_index(int device, int crtc_index,
>   					 char *fbc_status, int buf_size);
>   void intel_fbc_get_fbc_status(igt_crtc_t *crtc, char *fbc_status, int buf_size);
> +bool intel_fbc_found_skip_reason(int device, int crtc_index);
>   
>   #endif
> diff --git a/tests/intel/kms_frontbuffer_tracking.c b/tests/intel/kms_frontbuffer_tracking.c
> index 5bdfbd105..4fa185e76 100644
> --- a/tests/intel/kms_frontbuffer_tracking.c
> +++ b/tests/intel/kms_frontbuffer_tracking.c
> @@ -1652,51 +1652,6 @@ static bool fbc_wait_for_compression(void)
>   	return igt_wait(fbc_is_compressing(), 2000, 1);
>   }
>   
> -static bool fbc_not_enough_stolen(void)
> -{
> -	char fbc_status[128];
> -
> -	intel_fbc_get_fbc_status(prim_mode_params.crtc, fbc_status, sizeof(fbc_status));
> -
> -	return strstr(fbc_status, "FBC disabled: not enough stolen memory\n");
> -}
> -
> -static bool fbc_stride_not_supported(void)
> -{
> -	char fbc_status[128];
> -
> -	intel_fbc_get_fbc_status(prim_mode_params.crtc, fbc_status, sizeof(fbc_status));
> -
> -	return strstr(fbc_status, "FBC disabled: stride not supported\n");
> -}
> -
> -static bool fbc_plane_size_too_big(void)
> -{
> -	char fbc_status[128];
> -
> -	intel_fbc_get_fbc_status(prim_mode_params.crtc, fbc_status, sizeof(fbc_status));
> -
> -	return strstr(fbc_status, "FBC disabled: plane size too big\n");
> -}
> -
> -static bool fbc_surface_size_too_big(void)
> -{
> -	char fbc_status[128];
> -
> -	intel_fbc_get_fbc_status(prim_mode_params.crtc, fbc_status, sizeof(fbc_status));
> -
> -	return strstr(fbc_status, "FBC disabled: surface size too big\n");
> -}
> -
> -static bool fbc_psr_not_possible(void)
> -{
> -	char fbc_status[128];
> -
> -	intel_fbc_get_fbc_status(prim_mode_params.crtc, fbc_status, sizeof(fbc_status));
> -
> -	return strstr(fbc_status, "FBC disabled: PSR1 enabled (Wa_14016291713)");
> -}
> -
>   static bool fbc_enable_per_plane(int plane_index, igt_crtc_t *crtc)
>   {
>   	char fbc_status[PATH_MAX];
> @@ -2345,6 +2300,8 @@ static void do_crc_assertions(int flags)
>   
>   static void do_status_assertions(int flags)
>   {
> +	igt_crtc_t *crtc = prim_mode_params.crtc;
> +
>   	if (!opt.check_status) {
>   		/* Make sure we settle before continuing. */
>   		sleep(1);
> @@ -2362,27 +2319,25 @@ static void do_status_assertions(int flags)
>   			igt_assert_f(false, "DRRS LOW\n");
>   		}
>   	} else if (flags & ASSERT_DRRS_INACTIVE) {
> -		if (!intel_is_drrs_inactive(prim_mode_params.crtc)) {
> +		if (!intel_is_drrs_inactive(crtc)) {
>   			drrs_print_status();
>   			igt_assert_f(false, "DRRS INACTIVE\n");
>   		}
>   	}
>   
>   	if (flags & ASSERT_FBC_ENABLED) {
> -		igt_require(!fbc_not_enough_stolen());
> -		igt_require(!fbc_stride_not_supported());
> -		igt_require(!fbc_plane_size_too_big());
> -		igt_require(!fbc_surface_size_too_big());
> -		igt_require(!fbc_psr_not_possible());
> -		if (!intel_fbc_wait_until_enabled(prim_mode_params.crtc)) {
> -			igt_assert_f(intel_fbc_is_enabled(prim_mode_params.crtc, IGT_LOG_WARN),
> +		igt_require(!intel_fbc_found_skip_reason(crtc->display->drm_fd,
> +							 crtc->crtc_index));
> +
> +		if (!intel_fbc_wait_until_enabled(crtc)) {
> +			igt_assert_f(intel_fbc_is_enabled(crtc, IGT_LOG_WARN),
>   				     "FBC disabled\n");
>   		}
>   
>   		if (opt.fbc_check_compression)
>   			igt_assert(fbc_wait_for_compression());
>   	} else if (flags & ASSERT_FBC_DISABLED) {
> -		igt_assert(!intel_fbc_wait_until_enabled(prim_mode_params.crtc));
> +		igt_assert(!intel_fbc_wait_until_enabled(crtc));
>   	}
>   
>   	if (flags & ASSERT_PSR_ENABLED) {