[PATCH 12/87] drm/amd/display: early return when pipe_cnt is 0 in bw validation

[sunpeng.li at amd.com]

From: Eric Yang <Eric.Yang2 at amd.com>

[Why]
Unintentionally introduced behaviour change from previous refactor,
which causes clks to be 0 in no stream cases, which will cause
divide by 0.

[How]
Skip calculation of clocks when no stream. Which is the same as old
behaviour.

Signed-off-by: Eric Yang <Eric.Yang2 at amd.com>
Reviewed-by: Tony Cheng <tong.cheng at amd.com>
Acked-by: Leo Li <sunpeng.li at amd.com>
---
 drivers/gpu/drm/amd/display/dc/dcn20/dcn20_resource.c | 8 +++++++-
 drivers/gpu/drm/amd/display/dc/dcn20/dcn20_resource.h | 1 +
 2 files changed, 8 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/amd/display/dc/dcn20/dcn20_resource.c b/drivers/gpu/drm/amd/display/dc/dcn20/dcn20_resource.c
index d07d35a9dd0a..022d0f38723b 100644
--- a/drivers/gpu/drm/amd/display/dc/dcn20/dcn20_resource.c
+++ b/drivers/gpu/drm/amd/display/dc/dcn20/dcn20_resource.c
@@ -2020,6 +2020,7 @@ bool dcn20_fast_validate_bw(
 		struct dc *dc,
 		struct dc_state *context,
 		display_e2e_pipe_params_st *pipes,
+		int *pipe_cnt_out,
 		int *pipe_split_from,
 		int *vlevel_out)
 {
@@ -2072,6 +2073,8 @@ bool dcn20_fast_validate_bw(
 		pipe_cnt = dcn20_populate_dml_pipes_from_context(dc,
 			&context->res_ctx, pipes);
 
+	*pipe_cnt_out = pipe_cnt;
+
 	if (!pipe_cnt) {
 		out = true;
 		goto validate_out;
@@ -2432,7 +2435,10 @@ bool dcn20_validate_bandwidth(struct dc *dc, struct dc_state *context,
 
 	BW_VAL_TRACE_COUNT();
 
-	out = dcn20_fast_validate_bw(dc, context, pipes, pipe_split_from, &vlevel);
+	out = dcn20_fast_validate_bw(dc, context, pipes, &pipe_cnt, pipe_split_from, &vlevel);
+
+	if (pipe_cnt == 0)
+		goto validate_out;
 
 	if (!out)
 		goto validate_fail;
diff --git a/drivers/gpu/drm/amd/display/dc/dcn20/dcn20_resource.h b/drivers/gpu/drm/amd/display/dc/dcn20/dcn20_resource.h
index 2b3692e0c48d..44f95aa0d61e 100644
--- a/drivers/gpu/drm/amd/display/dc/dcn20/dcn20_resource.h
+++ b/drivers/gpu/drm/amd/display/dc/dcn20/dcn20_resource.h
@@ -120,6 +120,7 @@ bool dcn20_fast_validate_bw(
 		struct dc *dc,
 		struct dc_state *context,
 		display_e2e_pipe_params_st *pipes,
+		int *pipe_cnt_out,
 		int *pipe_split_from,
 		int *vlevel_out);
 void dcn20_calculate_dlg_params(
-- 
2.22.0