drm/amd/display: Check null-initialized variables

[WHAT & HOW]
drr_timing and subvp_pipe are initialized to null and they are not
always assigned new values. It is necessary to check for null before
dereferencing.

This fixes 2 FORWARD_NULL issues reported by Coverity.

Reviewed-by: Nevenko Stupar <nevenko.stupar@amd.com>
Reviewed-by: Rodrigo Siqueira <rodrigo.siqueira@amd.com>
Signed-off-by: Jerry Zuo <jerry.zuo@amd.com>
Signed-off-by: Alex Hung <alex.hung@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

diff --git a/drivers/gpu/drm/amd/display/dc/dml/dcn32/dcn32_fpu.c b/drivers/gpu/drm/amd/display/dc/dml/dcn32/dcn32_fpu.c
index 9d399c4ce957d5ba8bcd19ac4ca61e8f00182242..4cb0227bdd2707abd5cea527d7c8a06210828672 100644 (file)
--- a/drivers/gpu/drm/amd/display/dc/dml/dcn32/dcn32_fpu.c
+++ b/drivers/gpu/drm/amd/display/dc/dml/dcn32/dcn32_fpu.c
@@ -871,8 +871,9 @@ static bool subvp_drr_schedulable(struct dc *dc, struct dc_state *context)
         * for VBLANK: (VACTIVE region of the SubVP pipe can fit the MALL prefetch, VBLANK frame time,
         * and the max of (VBLANK blanking time, MALL region)).
         */
-       if (stretched_drr_us < (1 / (double)drr_timing->min_refresh_in_uhz) * 1000000 * 1000000 &&
-                       subvp_active_us - prefetch_us - stretched_drr_us - max_vblank_mallregion > 0)
+       if (drr_timing &&
+           stretched_drr_us < (1 / (double)drr_timing->min_refresh_in_uhz) * 1000000 * 1000000 &&
+           subvp_active_us - prefetch_us - stretched_drr_us - max_vblank_mallregion > 0)
                schedulable = true;
 
        return schedulable;
@@ -937,7 +938,7 @@ static bool subvp_vblank_schedulable(struct dc *dc, struct dc_state *context)
                if (!subvp_pipe && pipe_mall_type == SUBVP_MAIN)
                        subvp_pipe = pipe;
        }
-       if (found) {
+       if (found && subvp_pipe) {
                phantom_stream = dc_state_get_paired_subvp_stream(context, subvp_pipe->stream);
                main_timing = &subvp_pipe->stream->timing;
                phantom_timing = &phantom_stream->timing;