[PATCH 03/38] drm/amd/display: skip enable stream on disconnected display

[Bhawanpreet Lakha]

From: Wenjing Liu <Wenjing.Liu at amd.com>

[why]
Virtual signal means there is no display attached.
In this case we will assign a virtual signal type to the stream.
We should only enable the front end of the stream but not the back end.

[how]
When stream is enabling with virtual signal type, skip backend programming.

Change-Id: I8e1fe85a66eaa757aec88e1a0360f1fa6cee3397
Signed-off-by: Wenjing Liu <Wenjing.Liu at amd.com>
Reviewed-by: Jun Lei <Jun.Lei at amd.com>
Acked-by: Bhawanpreet Lakha <Bhawanpreet.Lakha at amd.com>
---
 drivers/gpu/drm/amd/display/dc/core/dc_link.c | 8 ++++++++
 1 file changed, 8 insertions(+)

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 33d4cc495ad1..17c972ca6beb 100644
--- a/drivers/gpu/drm/amd/display/dc/core/dc_link.c
+++ b/drivers/gpu/drm/amd/display/dc/core/dc_link.c
@@ -2718,6 +2718,10 @@ void core_link_enable_stream(
 	enum dc_status status;
 	DC_LOGGER_INIT(pipe_ctx->stream->ctx->logger);
 
+	if (!IS_FPGA_MAXIMUS_DC(core_dc->ctx->dce_environment) &&
+			dc_is_virtual_signal(pipe_ctx->stream->signal))
+		return;
+
 	if (!dc_is_virtual_signal(pipe_ctx->stream->signal)) {
 		stream->link->link_enc->funcs->setup(
 			stream->link->link_enc,
@@ -2860,6 +2864,10 @@ void core_link_disable_stream(struct pipe_ctx *pipe_ctx)
 	struct dc_stream_state *stream = pipe_ctx->stream;
 	struct dc_link *link = stream->sink->link;
 
+	if (!IS_FPGA_MAXIMUS_DC(core_dc->ctx->dce_environment) &&
+			dc_is_virtual_signal(pipe_ctx->stream->signal))
+		return;
+
 #if defined(CONFIG_DRM_AMD_DC_HDCP)
 	update_psp_stream_config(pipe_ctx, true);
 #endif
-- 
2.17.1