drm/amd/display: Prevent crash when disable stream

[Why]
Disabling stream encoder invokes a function that no longer exists.

[How]
Check if the function declaration is NULL in disable stream encoder.

Cc: Mario Limonciello <mario.limonciello@amd.com>
Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: stable@vger.kernel.org
Reviewed-by: Charlene Liu <charlene.liu@amd.com>
Acked-by: Wayne Lin <wayne.lin@amd.com>
Signed-off-by: Chris Park <chris.park@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/hwss/dce110/dce110_hwseq.c b/drivers/gpu/drm/amd/display/dc/hwss/dce110/dce110_hwseq.c
index 9d5df4c0da59796ebd8a16927cba72f17239c4fc..0ba1feaf96c0d76bceaf02c302e0e0f0f9c756ab 100644 (file)
--- a/drivers/gpu/drm/amd/display/dc/hwss/dce110/dce110_hwseq.c
+++ b/drivers/gpu/drm/amd/display/dc/hwss/dce110/dce110_hwseq.c
@@ -1185,7 +1185,8 @@ void dce110_disable_stream(struct pipe_ctx *pipe_ctx)
                if (dccg) {
                        dccg->funcs->disable_symclk32_se(dccg, dp_hpo_inst);
                        dccg->funcs->set_dpstreamclk(dccg, REFCLK, tg->inst, dp_hpo_inst);
-                       dccg->funcs->set_dtbclk_dto(dccg, &dto_params);
+                       if (dccg && dccg->funcs->set_dtbclk_dto)
+                               dccg->funcs->set_dtbclk_dto(dccg, &dto_params);
                }
        } else if (dccg && dccg->funcs->disable_symclk_se) {
                dccg->funcs->disable_symclk_se(dccg, stream_enc->stream_enc_inst,