[PATCH 6.6.y] drm/amd/display: Check denominator crb_pipes before used

From: Cliff Liu
Date: Thu Mar 27 2025 - 22:08:56 EST


From: Alex Hung <alex.hung@xxxxxxx>

[ Upstream commit ea79068d4073bf303f8203f2625af7d9185a1bc6 ]

[WHAT & HOW]
A denominator cannot be 0, and is checked before used.

This fixes 2 DIVIDE_BY_ZERO issues reported by Coverity.

Reviewed-by: Harry Wentland <harry.wentland@xxxxxxx>
Signed-off-by: Jerry Zuo <jerry.zuo@xxxxxxx>
Signed-off-by: Alex Hung <alex.hung@xxxxxxx>
Tested-by: Daniel Wheeler <daniel.wheeler@xxxxxxx>
Signed-off-by: Alex Deucher <alexander.deucher@xxxxxxx>
Signed-off-by: Cliff Liu <donghua.liu@xxxxxxxxxxxxx>
Signed-off-by: He Zhe <Zhe.He@xxxxxxxxxxxxx>
---
Verified the build test.
---
drivers/gpu/drm/amd/display/dc/dcn315/dcn315_resource.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/amd/display/dc/dcn315/dcn315_resource.c b/drivers/gpu/drm/amd/display/dc/dcn315/dcn315_resource.c
index 3f3b555b4523..597fa0364a3a 100644
--- a/drivers/gpu/drm/amd/display/dc/dcn315/dcn315_resource.c
+++ b/drivers/gpu/drm/amd/display/dc/dcn315/dcn315_resource.c
@@ -1753,7 +1753,7 @@ static int dcn315_populate_dml_pipes_from_context(
bool split_required = pipe->stream->timing.pix_clk_100hz >= dcn_get_max_non_odm_pix_rate_100hz(&dc->dml.soc)
|| (pipe->plane_state && pipe->plane_state->src_rect.width > 5120);

- if (remaining_det_segs > MIN_RESERVED_DET_SEGS)
+ if (remaining_det_segs > MIN_RESERVED_DET_SEGS && crb_pipes != 0)
pipes[pipe_cnt].pipe.src.det_size_override += (remaining_det_segs - MIN_RESERVED_DET_SEGS) / crb_pipes +
(crb_idx < (remaining_det_segs - MIN_RESERVED_DET_SEGS) % crb_pipes ? 1 : 0);
if (pipes[pipe_cnt].pipe.src.det_size_override > 2 * DCN3_15_MAX_DET_SEGS) {
--
2.43.0