[PATCH 08/16] drm/amd/display: enabling stream after HPD low to high happened

[Bhawanpreet Lakha]

From: Charlene Liu <charlene.liu at amd.com>

[Why]
1. No real HPD plug in/out but HPD happens,
 the driver notifies OS connection changed.
2. No display in target.

When HPD goes low to high,
the driver should regard as HPD and enter setmode flow.

[How]
In this case, even stream didn't change but still retrain.

Signed-off-by: Chiawen Huang <chiawen.huang at amd.com>
Reviewed-by: Tony Cheng <Tony.Cheng at amd.com>
Acked-by: Anthony Koo <Anthony.Koo at amd.com>
Acked-by: Bhawanpreet Lakha <Bhawanpreet.Lakha at amd.com>
---
 drivers/gpu/drm/amd/display/dc/core/dc_link.c               | 3 +++
 drivers/gpu/drm/amd/display/dc/core/dc_resource.c           | 4 ++++
 drivers/gpu/drm/amd/display/dc/dc_link.h                    | 1 +
 drivers/gpu/drm/amd/display/dc/dce110/dce110_hw_sequencer.c | 4 +++-
 4 files changed, 11 insertions(+), 1 deletion(-)

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 9fbf926d5bf9..6b8dc72a7861 100644
--- a/drivers/gpu/drm/amd/display/dc/core/dc_link.c
+++ b/drivers/gpu/drm/amd/display/dc/core/dc_link.c
@@ -704,6 +704,7 @@ bool dc_link_detect(struct dc_link *link, enum dc_detect_reason reason)
 
 	if (new_connection_type != dc_connection_none) {
 		link->type = new_connection_type;
+		link->link_state_valid = false;
 
 		/* From Disconnected-to-Connected. */
 		switch (link->connector_signal) {
@@ -2631,6 +2632,8 @@ void core_link_enable_stream(
 			stream->phy_pix_clk,
 			pipe_ctx->stream_res.audio != NULL);
 
+	pipe_ctx->stream->link->link_state_valid = true;
+
 	if (dc_is_dvi_signal(pipe_ctx->stream->signal))
 		pipe_ctx->stream_res.stream_enc->funcs->dvi_set_stream_attribute(
 			pipe_ctx->stream_res.stream_enc,
diff --git a/drivers/gpu/drm/amd/display/dc/core/dc_resource.c b/drivers/gpu/drm/amd/display/dc/core/dc_resource.c
index 36346f6ceb9a..3bb19890c9b7 100644
--- a/drivers/gpu/drm/amd/display/dc/core/dc_resource.c
+++ b/drivers/gpu/drm/amd/display/dc/core/dc_resource.c
@@ -2646,6 +2646,10 @@ bool pipe_need_reprogram(
 	if (is_vsc_info_packet_changed(pipe_ctx_old->stream, pipe_ctx->stream))
 		return true;
 
+	if (false == pipe_ctx_old->stream->link->link_state_valid &&
+		false == pipe_ctx_old->stream->dpms_off)
+		return true;
+
 	return false;
 }
 
diff --git a/drivers/gpu/drm/amd/display/dc/dc_link.h b/drivers/gpu/drm/amd/display/dc/dc_link.h
index 7b9429e30d82..094009127e25 100644
--- a/drivers/gpu/drm/amd/display/dc/dc_link.h
+++ b/drivers/gpu/drm/amd/display/dc/dc_link.h
@@ -75,6 +75,7 @@ struct dc_link {
 	enum dc_irq_source irq_source_hpd_rx;/* aka DP Short Pulse  */
 	bool is_hpd_filter_disabled;
 	bool dp_ss_off;
+	bool link_state_valid;
 
 	/* caps is the same as reported_link_cap. link_traing use
 	 * reported_link_cap. Will clean up.  TODO
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 d3c821f3899b..69f215967af3 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
@@ -2023,8 +2023,10 @@ enum dc_status dce110_apply_ctx_to_hw(
 		if (pipe_ctx->stream == NULL)
 			continue;
 
-		if (pipe_ctx->stream == pipe_ctx_old->stream)
+		if (pipe_ctx->stream == pipe_ctx_old->stream &&
+			pipe_ctx->stream->link->link_state_valid) {
 			continue;
+		}
 
 		if (pipe_ctx_old->stream && !pipe_need_reprogram(pipe_ctx_old, pipe_ctx))
 			continue;
-- 
2.17.1