[PATCH] drm/amd/display: add NULL checks for clock manager pointer

[Alex Deucher]

From: Ahzo <Ahzo at tutanota.com>

This fixes kernel NULL pointer dereferences on shutdown:
RIP: 0010:build_audio_output.isra.0+0x97/0x110 [amdgpu]
RIP: 0010:enable_link_dp+0x186/0x300 [amdgpu]

Signed-off-by: Ahzo <Ahzo at tutanota.com>
Signed-off-by: Alex Deucher <alexander.deucher at amd.com>
---
 drivers/gpu/drm/amd/display/dc/core/dc_link.c               | 2 +-
 drivers/gpu/drm/amd/display/dc/dce110/dce110_hw_sequencer.c | 5 +++--
 2 files changed, 4 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/amd/display/dc/core/dc_link.c b/drivers/gpu/drm/amd/display/dc/core/dc_link.c
index 152c564a8344..8b58cfa3e98e 100644
--- a/drivers/gpu/drm/amd/display/dc/core/dc_link.c
+++ b/drivers/gpu/drm/amd/display/dc/core/dc_link.c
@@ -1510,7 +1510,7 @@ static enum dc_status enable_link_dp(
 
 	pipe_ctx->stream_res.pix_clk_params.requested_sym_clk =
 			link_settings.link_rate * LINK_RATE_REF_FREQ_IN_KHZ;
-	if (!apply_seamless_boot_optimization)
+	if (state->clk_mgr && !apply_seamless_boot_optimization)
 		state->clk_mgr->funcs->update_clocks(state->clk_mgr, state, false);
 
 	dp_enable_link_phy(
diff --git a/drivers/gpu/drm/amd/display/dc/dce110/dce110_hw_sequencer.c b/drivers/gpu/drm/amd/display/dc/dce110/dce110_hw_sequencer.c
index f8c1b4f1b987..8d8fa10b5d86 100644
--- a/drivers/gpu/drm/amd/display/dc/dce110/dce110_hw_sequencer.c
+++ b/drivers/gpu/drm/amd/display/dc/dce110/dce110_hw_sequencer.c
@@ -1161,8 +1161,9 @@ static void build_audio_output(
 		}
 	}
 
-	if (pipe_ctx->stream->signal == SIGNAL_TYPE_DISPLAY_PORT ||
-			pipe_ctx->stream->signal == SIGNAL_TYPE_DISPLAY_PORT_MST) {
+	if (state->clk_mgr &&
+		(pipe_ctx->stream->signal == SIGNAL_TYPE_DISPLAY_PORT ||
+			pipe_ctx->stream->signal == SIGNAL_TYPE_DISPLAY_PORT_MST)) {
 		audio_output->pll_info.dp_dto_source_clock_in_khz =
 				state->clk_mgr->funcs->get_dp_ref_clk_frequency(
 						state->clk_mgr);
-- 
2.20.1