[PATCH] drm/amd/display: Add NULL test for 'timing generator' in 'dcn21_set_pipe()'

[Srinivasan Shanmugam]

In "u32 otg_inst = pipe_ctx->stream_res.tg->inst;"
pipe_ctx->stream_res.tg could be NULL, it is relying on the caller to
ensure the tg is not NULL.

Fixes: 474ac4a875ca ("drm/amd/display: Implement some asic specific abm call 
backs.")
Cc: Yongqiang Sun <yongqiang....@amd.com>
Cc: Anthony Koo <anthony....@amd.com>
Cc: Rodrigo Siqueira <rodrigo.sique...@amd.com>
Cc: Aurabindo Pillai <aurabindo.pil...@amd.com>
Signed-off-by: Srinivasan Shanmugam <srinivasan.shanmu...@amd.com>
---
 .../amd/display/dc/hwss/dcn21/dcn21_hwseq.c   | 24 +++++++++++--------
 1 file changed, 14 insertions(+), 10 deletions(-)

diff --git a/drivers/gpu/drm/amd/display/dc/hwss/dcn21/dcn21_hwseq.c 
b/drivers/gpu/drm/amd/display/dc/hwss/dcn21/dcn21_hwseq.c
index 5d2d8fd64d98..4e21af0942ea 100644
--- a/drivers/gpu/drm/amd/display/dc/hwss/dcn21/dcn21_hwseq.c
+++ b/drivers/gpu/drm/amd/display/dc/hwss/dcn21/dcn21_hwseq.c
@@ -206,28 +206,32 @@ void dcn21_set_abm_immediate_disable(struct pipe_ctx 
*pipe_ctx)
 void dcn21_set_pipe(struct pipe_ctx *pipe_ctx)
 {
        struct abm *abm = pipe_ctx->stream_res.abm;
-       uint32_t otg_inst = pipe_ctx->stream_res.tg->inst;
+       struct timing_generator *tg = pipe_ctx->stream_res.tg;
        struct panel_cntl *panel_cntl = pipe_ctx->stream->link->panel_cntl;
        struct dmcu *dmcu = pipe_ctx->stream->ctx->dc->res_pool->dmcu;
+       u32 otg_inst;
+
+       if (!abm && !tg && !panel_cntl)
+               return;
+
+       otg_inst = tg->inst;
 
        if (dmcu) {
                dce110_set_pipe(pipe_ctx);
                return;
        }
 
-       if (abm && panel_cntl) {
-               if (abm->funcs && abm->funcs->set_pipe_ex) {
-                       abm->funcs->set_pipe_ex(abm,
+       if (abm->funcs && abm->funcs->set_pipe_ex) {
+               abm->funcs->set_pipe_ex(abm,
                                        otg_inst,
                                        SET_ABM_PIPE_NORMAL,
                                        panel_cntl->inst,
                                        panel_cntl->pwrseq_inst);
-               } else {
-                               dmub_abm_set_pipe(abm, otg_inst,
-                                               SET_ABM_PIPE_NORMAL,
-                                               panel_cntl->inst,
-                                               panel_cntl->pwrseq_inst);
-               }
+       } else {
+               dmub_abm_set_pipe(abm, otg_inst,
+                                 SET_ABM_PIPE_NORMAL,
+                                 panel_cntl->inst,
+                                 panel_cntl->pwrseq_inst);
        }
 }
 
-- 
2.34.1