[PATCH] drm/amd/display: Fix unsigned comparison with less than zero

From: Jiapeng Chong
Date: Sun Jun 30 2024 - 22:50:58 EST


The return value from the call to dml21_find_dc_pipes_for_plane() is int.
However, the return value is being assigned to an unsigned int variable
'num_pipes', the condition if(num_pipes <= 0) is not rigorous enough,
so making 'num_pipes' an int.

./drivers/gpu/drm/amd/display/dc/dml2/dml21/dml21_wrapper.c:318:6-15: WARNING: Unsigned expression compared with zero: num_pipes <= 0.
./drivers/gpu/drm/amd/display/dc/dml2/dml21/dml21_wrapper.c:360:6-15: WARNING: Unsigned expression compared with zero: num_pipes <= 0.

Reported-by: Abaci Robot <abaci@xxxxxxxxxxxxxxxxx>
Closes: https://bugzilla.openanolis.cn/show_bug.cgi?id=9454
Signed-off-by: Jiapeng Chong <jiapeng.chong@xxxxxxxxxxxxxxxxx>
---
.../drm/amd/display/dc/dml2/dml21/dml21_wrapper.c | 15 ++++++---------
1 file changed, 6 insertions(+), 9 deletions(-)

diff --git a/drivers/gpu/drm/amd/display/dc/dml2/dml21/dml21_wrapper.c b/drivers/gpu/drm/amd/display/dc/dml2/dml21/dml21_wrapper.c
index c310354cd5fc..9d96a31419fa 100644
--- a/drivers/gpu/drm/amd/display/dc/dml2/dml21/dml21_wrapper.c
+++ b/drivers/gpu/drm/amd/display/dc/dml2/dml21/dml21_wrapper.c
@@ -280,7 +280,8 @@ bool dml21_validate(const struct dc *in_dc, struct dc_state *context, struct dml

void dml21_prepare_mcache_programming(struct dc *in_dc, struct dc_state *context, struct dml2_context *dml_ctx)
{
- unsigned int num_pipes, dml_prog_idx, dml_phantom_prog_idx, dc_pipe_index;
+ unsigned int dml_prog_idx, dml_phantom_prog_idx, dc_pipe_index;
+ int num_pipes;
struct pipe_ctx *dc_main_pipes[__DML2_WRAPPER_MAX_STREAMS_PLANES__];
struct pipe_ctx *dc_phantom_pipes[__DML2_WRAPPER_MAX_STREAMS_PLANES__] = {0};

@@ -314,10 +315,8 @@ void dml21_prepare_mcache_programming(struct dc *in_dc, struct dc_state *context
}

num_pipes = dml21_find_dc_pipes_for_plane(in_dc, context, dml_ctx, dc_main_pipes, dc_phantom_pipes, dml_prog_idx);
-
- if (num_pipes <= 0 ||
- dc_main_pipes[0]->stream == NULL ||
- dc_main_pipes[0]->plane_state == NULL)
+ if (num_pipes <= 0 || dc_main_pipes[0]->stream == NULL ||
+ dc_main_pipes[0]->plane_state == NULL)
continue;

/* get config for each pipe */
@@ -356,10 +355,8 @@ void dml21_prepare_mcache_programming(struct dc *in_dc, struct dc_state *context
pln_prog = &dml_ctx->v21.mode_programming.programming->plane_programming[dml_prog_idx];

num_pipes = dml21_find_dc_pipes_for_plane(in_dc, context, dml_ctx, dc_main_pipes, dc_phantom_pipes, dml_prog_idx);
-
- if (num_pipes <= 0 ||
- dc_main_pipes[0]->stream == NULL ||
- dc_main_pipes[0]->plane_state == NULL)
+ if (num_pipes <= 0 || dc_main_pipes[0]->stream == NULL ||
+ dc_main_pipes[0]->plane_state == NULL)
continue;

/* get config for each pipe */
--
2.20.1.7.g153144c