[PATCH] drm/amd/display: avoid large stack allocation in commit_planes_do_stream_update_sequence

[PATCH] drm/amd/display: avoid large stack allocation in commit_planes_do_stream_update_sequence

[Arnd Bergmann]

From: Arnd Bergmann <arnd@arndb.de>

The function has two arrays on the stack to hold temporary dsc_optc_config
and dsc_config objects. The combination blows through common stack frame
warning limits in combination with the other local variables:

drivers/gpu/drm/amd/amdgpu/../display/dc/core/dc.c:4070:22: error: stack frame size (1352) exceeds limit
      (1280) in 'commit_planes_do_stream_update_sequence' [-Werror,-Wframe-larger-than]

Since neither array is initialized or used outside of the
add_link_update_dsc_config_sequence() function, there is no actual
need to keep each element around.

Replace the arrays with a single instance each to reduce the stack usage
to less than half.

Fixes: 9f49d3cd7e71 ("drm/amd/display: Implement block sequencing infrastructure for modular hardware operations.")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
 drivers/gpu/drm/amd/display/dc/core/dc.c | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/drivers/gpu/drm/amd/display/dc/core/dc.c b/drivers/gpu/drm/amd/display/dc/core/dc.c
index bcdbf3471039..72762c4fa392 100644
--- a/drivers/gpu/drm/amd/display/dc/core/dc.c
+++ b/drivers/gpu/drm/amd/display/dc/core/dc.c
@@ -4077,8 +4077,6 @@ static void commit_planes_do_stream_update_sequence(struct dc *dc,
 {
 	int j;
 	struct block_sequence_state seq_state = { .steps = block_sequence, .num_steps = num_steps };
-	struct dsc_config dsc_cfgs[MAX_PIPES];
-	struct dsc_optc_config dsc_optc_cfgs[MAX_PIPES];
 	unsigned int dsc_cfg_index = 0;
 	*num_steps = 0; // Initialize to 0
 
@@ -4150,11 +4148,13 @@ static void commit_planes_do_stream_update_sequence(struct dc *dc,
 
 			if (stream_update->dsc_config)
 				if (dsc_cfg_index < MAX_PIPES) {
+					struct dsc_config dsc_cfg;
+					struct dsc_optc_config dsc_optc_cfg;
+
 					add_link_update_dsc_config_sequence(&seq_state,
 						pipe_ctx,
-						&dsc_cfgs[dsc_cfg_index],
-						&dsc_optc_cfgs[dsc_cfg_index]);
-					dsc_cfg_index++;
+						&dsc_cfg,
+						&dsc_optc_cfg);
 				}
 
 			if (stream_update->mst_bw_update) {
-- 
2.39.5