[PATCH v3] drm/amd/display: Reduce Stack Usage by moving 'audio_output' into 'stream_res' v3

Srinivasan Shanmugam srinivasan.shanmugam at amd.com
Thu Jul 24 09:31:51 UTC 2025


The function `dp_retrain_link_dp_test` currently allocates a large
audio_output array on the stack, causing the stack frame size to exceed
the compiler limit (1080 bytes > 1024 bytes).

This change prevents stack overflow issues:
amdgpu/../display/dc/link/accessories/link_dp_cts.c:65:13: warning: stack frame size (1080) exceeds limit (1024) in 'dp_retrain_link_dp_test' [-Wframe-larger-than]
static void dp_retrain_link_dp_test(struct dc_link *link,

v2: Move audio-related data like `audio_output` is kept "per pipe" to
    manage the audio for that specific display pipeline/display output path
    (stream). (Wenjing)

v3: Update in all the places where `build_audio_output` is currently
    called with a separate audio_output variable on the stack & wherever
    `audio_output` is passed to other functions
    `dce110_apply_single_controller_ctx_to_hw()` &
    `dce110_setup_audio_dto()` (like `az_configure`, `wall_dto_setup`)
    replace with usage of `pipe_ctx->stream_res.audio_output`
    to centralize audio data per pipe.

'Fixes: 9437059b4bfb ("drm/amd/display: Fix Link Override Sequencing When
Switching Between DIO/HPO")'
Cc: Wayne Lin <wayne.lin at amd.com>
Cc: George Shen <george.shen at amd.com>
Cc: Michael Strauss <michael.strauss at amd.com>
Cc: Alvin Lee <Alvin.Lee2 at amd.com>
Cc: Ray Wu <ray.wu at amd.com>
Cc: Wenjing Liu <wenjing.liu at amd.com>
Cc: Harry Wentland <harry.wentland at amd.com>
Cc: Tom Chung <chiahsuan.chung at amd.com>
Cc: Roman Li <roman.li at amd.com>
Cc: Alex Hung <alex.hung at amd.com>
Cc: Aurabindo Pillai <aurabindo.pillai at amd.com>
Signed-off-by: Srinivasan Shanmugam <srinivasan.shanmugam at amd.com>
---
 .../amd/display/dc/hwss/dce110/dce110_hwseq.c | 29 +++++++++----------
 .../gpu/drm/amd/display/dc/inc/core_types.h   |  5 ++--
 .../display/dc/link/accessories/link_dp_cts.c | 12 ++++----
 .../dc/resource/dcn31/dcn31_resource.c        |  5 ++--
 .../dc/resource/dcn31/dcn31_resource.h        |  3 +-
 5 files changed, 26 insertions(+), 28 deletions(-)

diff --git a/drivers/gpu/drm/amd/display/dc/hwss/dce110/dce110_hwseq.c b/drivers/gpu/drm/amd/display/dc/hwss/dce110/dce110_hwseq.c
index 4ea13d0bf815..0846338a4b4a 100644
--- a/drivers/gpu/drm/amd/display/dc/hwss/dce110/dce110_hwseq.c
+++ b/drivers/gpu/drm/amd/display/dc/hwss/dce110/dce110_hwseq.c
@@ -1600,19 +1600,18 @@ enum dc_status dce110_apply_single_controller_ctx_to_hw(
 	}
 
 	if (pipe_ctx->stream_res.audio != NULL) {
-		struct audio_output audio_output = {0};
 
-		build_audio_output(context, pipe_ctx, &audio_output);
+		build_audio_output(context, pipe_ctx, &pipe_ctx->stream_res.audio_output);
 
-		link_hwss->setup_audio_output(pipe_ctx, &audio_output,
+		link_hwss->setup_audio_output(pipe_ctx, &pipe_ctx->stream_res.audio_output,
 				pipe_ctx->stream_res.audio->inst);
 
 		pipe_ctx->stream_res.audio->funcs->az_configure(
 				pipe_ctx->stream_res.audio,
 				pipe_ctx->stream->signal,
-				&audio_output.crtc_info,
+				&pipe_ctx->stream_res.audio_output.crtc_info,
 				&pipe_ctx->stream->audio_info,
-				&audio_output.dp_link_info);
+				&pipe_ctx->stream_res.audio_output.dp_link_info);
 
 		if (dc->config.disable_hbr_audio_dp2)
 			if (pipe_ctx->stream_res.audio->funcs->az_disable_hbr_audio &&
@@ -2386,9 +2385,8 @@ static void dce110_setup_audio_dto(
 		if (pipe_ctx->stream->signal != SIGNAL_TYPE_HDMI_TYPE_A)
 			continue;
 		if (pipe_ctx->stream_res.audio != NULL) {
-			struct audio_output audio_output;
 
-			build_audio_output(context, pipe_ctx, &audio_output);
+			build_audio_output(context, pipe_ctx, &pipe_ctx->stream_res.audio_output);
 
 			if (dc->res_pool->dccg && dc->res_pool->dccg->funcs->set_audio_dtbclk_dto) {
 				struct dtbclk_dto_params dto_params = {0};
@@ -2399,14 +2397,14 @@ static void dce110_setup_audio_dto(
 				pipe_ctx->stream_res.audio->funcs->wall_dto_setup(
 						pipe_ctx->stream_res.audio,
 						pipe_ctx->stream->signal,
-						&audio_output.crtc_info,
-						&audio_output.pll_info);
+						&pipe_ctx->stream_res.audio_output.crtc_info,
+						&pipe_ctx->stream_res.audio_output.pll_info);
 			} else
 				pipe_ctx->stream_res.audio->funcs->wall_dto_setup(
 					pipe_ctx->stream_res.audio,
 					pipe_ctx->stream->signal,
-					&audio_output.crtc_info,
-					&audio_output.pll_info);
+					&pipe_ctx->stream_res.audio_output.crtc_info,
+					&pipe_ctx->stream_res.audio_output.pll_info);
 			break;
 		}
 	}
@@ -2426,15 +2424,16 @@ static void dce110_setup_audio_dto(
 				continue;
 
 			if (pipe_ctx->stream_res.audio != NULL) {
-				struct audio_output audio_output = {0};
 
-				build_audio_output(context, pipe_ctx, &audio_output);
+				build_audio_output(context,
+						   pipe_ctx,
+						   &pipe_ctx->stream_res.audio_output);
 
 				pipe_ctx->stream_res.audio->funcs->wall_dto_setup(
 					pipe_ctx->stream_res.audio,
 					pipe_ctx->stream->signal,
-					&audio_output.crtc_info,
-					&audio_output.pll_info);
+					&pipe_ctx->stream_res.audio_output.crtc_info,
+					&pipe_ctx->stream_res.audio_output.pll_info);
 				break;
 			}
 		}
diff --git a/drivers/gpu/drm/amd/display/dc/inc/core_types.h b/drivers/gpu/drm/amd/display/dc/inc/core_types.h
index f0d7185153b2..f896cce87b8d 100644
--- a/drivers/gpu/drm/amd/display/dc/inc/core_types.h
+++ b/drivers/gpu/drm/amd/display/dc/inc/core_types.h
@@ -228,8 +228,7 @@ struct resource_funcs {
 	enum dc_status (*update_dc_state_for_encoder_switch)(struct dc_link *link,
 		struct dc_link_settings *link_setting,
 		uint8_t pipe_count,
-		struct pipe_ctx *pipes,
-		struct audio_output *audio_output);
+		struct pipe_ctx *pipes);
 };
 
 struct audio_support{
@@ -361,6 +360,8 @@ struct stream_resource {
 	uint8_t gsl_group;
 
 	struct test_pattern_params test_pattern_params;
+
+	struct audio_output audio_output;
 };
 
 struct plane_resource {
diff --git a/drivers/gpu/drm/amd/display/dc/link/accessories/link_dp_cts.c b/drivers/gpu/drm/amd/display/dc/link/accessories/link_dp_cts.c
index 2956c2b3ad1a..b12d61701d4d 100644
--- a/drivers/gpu/drm/amd/display/dc/link/accessories/link_dp_cts.c
+++ b/drivers/gpu/drm/amd/display/dc/link/accessories/link_dp_cts.c
@@ -75,7 +75,6 @@ static void dp_retrain_link_dp_test(struct dc_link *link,
 	bool is_hpo_acquired;
 	uint8_t count;
 	int i;
-	struct audio_output audio_output[MAX_PIPES];
 
 	needs_divider_update = (link->dc->link_srv->dp_get_encoding_format(link_setting) !=
 	link->dc->link_srv->dp_get_encoding_format((const struct dc_link_settings *) &link->cur_link_settings));
@@ -99,7 +98,7 @@ static void dp_retrain_link_dp_test(struct dc_link *link,
 	if (needs_divider_update && link->dc->res_pool->funcs->update_dc_state_for_encoder_switch) {
 		link->dc->res_pool->funcs->update_dc_state_for_encoder_switch(link,
 				link_setting, count,
-				*pipes, &audio_output[0]);
+				*pipes);
 		for (i = 0; i < count; i++) {
 			pipes[i]->clock_source->funcs->program_pix_clk(
 					pipes[i]->clock_source,
@@ -111,15 +110,16 @@ static void dp_retrain_link_dp_test(struct dc_link *link,
 				const struct link_hwss *link_hwss = get_link_hwss(
 					link, &pipes[i]->link_res);
 
-				link_hwss->setup_audio_output(pipes[i], &audio_output[i],
-						pipes[i]->stream_res.audio->inst);
+				link_hwss->setup_audio_output(pipes[i],
+							      &pipes[i]->stream_res.audio_output,
+							      pipes[i]->stream_res.audio->inst);
 
 				pipes[i]->stream_res.audio->funcs->az_configure(
 						pipes[i]->stream_res.audio,
 						pipes[i]->stream->signal,
-						&audio_output[i].crtc_info,
+						&pipes[i]->stream_res.audio_output.crtc_info,
 						&pipes[i]->stream->audio_info,
-						&audio_output[i].dp_link_info);
+						&pipes[i]->stream_res.audio_output.dp_link_info);
 
 				if (link->dc->config.disable_hbr_audio_dp2 &&
 						pipes[i]->stream_res.audio->funcs->az_disable_hbr_audio &&
diff --git a/drivers/gpu/drm/amd/display/dc/resource/dcn31/dcn31_resource.c b/drivers/gpu/drm/amd/display/dc/resource/dcn31/dcn31_resource.c
index 3ed7f50554e2..ca17e5d8fdc2 100644
--- a/drivers/gpu/drm/amd/display/dc/resource/dcn31/dcn31_resource.c
+++ b/drivers/gpu/drm/amd/display/dc/resource/dcn31/dcn31_resource.c
@@ -2239,8 +2239,7 @@ struct resource_pool *dcn31_create_resource_pool(
 enum dc_status dcn31_update_dc_state_for_encoder_switch(struct dc_link *link,
 	struct dc_link_settings *link_setting,
 	uint8_t pipe_count,
-	struct pipe_ctx *pipes,
-	struct audio_output *audio_output)
+	struct pipe_ctx *pipes)
 {
 	struct dc_state *state = link->dc->current_state;
 	int i;
@@ -2255,7 +2254,7 @@ enum dc_status dcn31_update_dc_state_for_encoder_switch(struct dc_link *link,
 
 		// Setup audio
 		if (pipes[i].stream_res.audio != NULL)
-			build_audio_output(state, &pipes[i], &audio_output[i]);
+			build_audio_output(state, &pipes[i], &pipes[i].stream_res.audio_output);
 	}
 #else
 	/* This DCN requires rate divider updates and audio reprogramming to allow DP1<-->DP2 link rate switching,
diff --git a/drivers/gpu/drm/amd/display/dc/resource/dcn31/dcn31_resource.h b/drivers/gpu/drm/amd/display/dc/resource/dcn31/dcn31_resource.h
index c32c85ef0ba4..7e8fde65528f 100644
--- a/drivers/gpu/drm/amd/display/dc/resource/dcn31/dcn31_resource.h
+++ b/drivers/gpu/drm/amd/display/dc/resource/dcn31/dcn31_resource.h
@@ -69,8 +69,7 @@ unsigned int dcn31_get_det_buffer_size(
 enum dc_status dcn31_update_dc_state_for_encoder_switch(struct dc_link *link,
 	struct dc_link_settings *link_setting,
 	uint8_t pipe_count,
-	struct pipe_ctx *pipes,
-	struct audio_output *audio_output);
+	struct pipe_ctx *pipes);
 
 /*temp: B0 specific before switch to dcn313 headers*/
 #ifndef regPHYPLLF_PIXCLK_RESYNC_CNTL
-- 
2.34.1



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