[PATCH 08/10] drm/amd/display: Use DTO as clock on DP if not

[Harry Wentland]

From: Ding Wang <Ding.Wang at amd.com>

Use DVO as pixel clock for DP before enabling link
PHY. Otherwise, when switching from HDMI passive dongle
to DP on the same connector, the PHY PLL is used as
pixel clock, and CRTC would stop working.

Change-Id: Iad2e20eaac6675ce53f9fec6781e75151c43666f
Signed-off-by: Ding Wang <Ding.Wang at amd.com>
Reviewed-by: Tony Cheng <Tony.Cheng at amd.com>
Acked-by: Harry Wentland <Harry.Wentland at amd.com>
---
 drivers/gpu/drm/amd/display/dc/core/dc_link_hwss.c | 25 ++++++++++++++++++++++
 1 file changed, 25 insertions(+)

diff --git a/drivers/gpu/drm/amd/display/dc/core/dc_link_hwss.c b/drivers/gpu/drm/amd/display/dc/core/dc_link_hwss.c
index da49be0672d7..55d96656e54b 100644
--- a/drivers/gpu/drm/amd/display/dc/core/dc_link_hwss.c
+++ b/drivers/gpu/drm/amd/display/dc/core/dc_link_hwss.c
@@ -61,6 +61,31 @@ void dp_enable_link_phy(
 {
 	struct link_encoder *link_enc = link->link_enc;
 
+	struct pipe_ctx *pipes =
+			link->dc->current_context->res_ctx.pipe_ctx;
+	struct clock_source *dp_cs =
+			link->dc->res_pool->dp_clock_source;
+	unsigned int i;
+	/* If the current pixel clock source is not DTO(happens after
+	 * switching from HDMI passive dongle to DP on the same connector),
+	 * switch the pixel clock source to DTO.
+	 */
+	for (i = 0; i < MAX_PIPES; i++) {
+		if (pipes[i].stream != NULL &&
+			pipes[i].stream->sink != NULL &&
+			pipes[i].stream->sink->link == link) {
+			if (pipes[i].clock_source->id != CLOCK_SOURCE_ID_DP_DTO) {
+				pipes[i].clock_source = dp_cs;
+				pipes[i].pix_clk_params.requested_pix_clk =
+						pipes[i].stream->public.timing.pix_clk_khz;
+				pipes[i].clock_source->funcs->program_pix_clk(
+							pipes[i].clock_source,
+							&pipes[i].pix_clk_params,
+							&pipes[i].pll_settings);
+			}
+		}
+	}
+
 	if (dc_is_dp_sst_signal(signal)) {
 		if (signal == SIGNAL_TYPE_EDP) {
 			link_enc->funcs->power_control(link_enc, true);
-- 
2.9.3