drm/amd/display: Assume LTTPR interop for DCN31+

[WHY]
For DCN31 onward, LTTPR is to be enabled and set to Transparent by
VBIOS.  Driver is to assume that VBIOS has done this without needing to
check the VBIOS interop bit.

[HOW]
Add LTTPR enable and interop VBIOS bits into dc->caps, and force-set the
interop bit to true for DCN31+.

Reviewed-by: Jun Lei <Jun.Lei@amd.com>
Acked-by: Aurabindo Pillai <aurabindo.pillai@amd.com>
Signed-off-by: Wesley Chalmers <Wesley.Chalmers@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

4 files changed, 40 insertions, 19 deletions

diff --git a/drivers/gpu/drm/amd/display/dc/core/dc_link_dp.c b/drivers/gpu/drm/amd/display/dc/core/dc_link_dp.c
index 9fb8c46dc606..a6d0fd24fd02 100644
--- a/drivers/gpu/drm/amd/display/dc/core/dc_link_dp.c
+++ b/drivers/gpu/drm/amd/display/dc/core/dc_link_dp.c
@@ -3602,29 +3602,12 @@ static bool dpcd_read_sink_ext_caps(struct dc_link *link)
 bool dp_retrieve_lttpr_cap(struct dc_link *link)
 {
 	uint8_t lttpr_dpcd_data[6];
-	bool vbios_lttpr_enable = false;
-	bool vbios_lttpr_interop = false;
-	struct dc_bios *bios = link->dc->ctx->dc_bios;
+	bool vbios_lttpr_enable = link->dc->caps.vbios_lttpr_enable;
+	bool vbios_lttpr_interop = link->dc->caps.vbios_lttpr_aware;
 	enum dc_status status = DC_ERROR_UNEXPECTED;
 	bool is_lttpr_present = false;
 
 	memset(lttpr_dpcd_data, '\0', sizeof(lttpr_dpcd_data));
-	/* Query BIOS to determine if LTTPR functionality is forced on by system */
-	if (bios->funcs->get_lttpr_caps) {
-		enum bp_result bp_query_result;
-		uint8_t is_vbios_lttpr_enable = 0;
-
-		bp_query_result = bios->funcs->get_lttpr_caps(bios, &is_vbios_lttpr_enable);
-		vbios_lttpr_enable = (bp_query_result == BP_RESULT_OK) && !!is_vbios_lttpr_enable;
-	}
-
-	if (bios->funcs->get_lttpr_interop) {
-		enum bp_result bp_query_result;
-		uint8_t is_vbios_interop_enabled = 0;
-
-		bp_query_result = bios->funcs->get_lttpr_interop(bios, &is_vbios_interop_enabled);
-		vbios_lttpr_interop = (bp_query_result == BP_RESULT_OK) && !!is_vbios_interop_enabled;
-	}
 
 	/*
 	 * Logic to determine LTTPR mode
diff --git a/drivers/gpu/drm/amd/display/dc/dc.h b/drivers/gpu/drm/amd/display/dc/dc.h
index 8dcea8ff5c5a..af7b60108e9d 100644
--- a/drivers/gpu/drm/amd/display/dc/dc.h
+++ b/drivers/gpu/drm/amd/display/dc/dc.h
@@ -183,6 +183,8 @@ struct dc_caps {
 	unsigned int cursor_cache_size;
 	struct dc_plane_cap planes[MAX_PLANES];
 	struct dc_color_caps color;
+	bool vbios_lttpr_aware;
+	bool vbios_lttpr_enable;
 };
 
 struct dc_bug_wa {
diff --git a/drivers/gpu/drm/amd/display/dc/dcn30/dcn30_resource.c b/drivers/gpu/drm/amd/display/dc/dcn30/dcn30_resource.c
index 596c97dce67e..253654d605c2 100644
--- a/drivers/gpu/drm/amd/display/dc/dcn30/dcn30_resource.c
+++ b/drivers/gpu/drm/amd/display/dc/dcn30/dcn30_resource.c
@@ -2617,6 +2617,26 @@ static bool dcn30_resource_construct(
 	dc->caps.color.mpc.ogam_rom_caps.hlg = 0;
 	dc->caps.color.mpc.ocsc = 1;
 
+	/* read VBIOS LTTPR caps */
+	{
+		if (ctx->dc_bios->funcs->get_lttpr_caps) {
+			enum bp_result bp_query_result;
+			uint8_t is_vbios_lttpr_enable = 0;
+
+			bp_query_result = ctx->dc_bios->funcs->get_lttpr_caps(ctx->dc_bios, &is_vbios_lttpr_enable);
+			dc->caps.vbios_lttpr_enable = (bp_query_result == BP_RESULT_OK) && !!is_vbios_lttpr_enable;
+		}
+
+		if (ctx->dc_bios->funcs->get_lttpr_interop) {
+			enum bp_result bp_query_result;
+			uint8_t is_vbios_interop_enabled = 0;
+
+			bp_query_result = ctx->dc_bios->funcs->get_lttpr_interop(ctx->dc_bios,
+					&is_vbios_interop_enabled);
+			dc->caps.vbios_lttpr_aware = (bp_query_result == BP_RESULT_OK) && !!is_vbios_interop_enabled;
+		}
+	}
+
 	if (dc->ctx->dce_environment == DCE_ENV_PRODUCTION_DRV)
 		dc->debug = debug_defaults_drv;
 	else if (dc->ctx->dce_environment == DCE_ENV_FPGA_MAXIMUS) {
diff --git a/drivers/gpu/drm/amd/display/dc/dcn31/dcn31_resource.c b/drivers/gpu/drm/amd/display/dc/dcn31/dcn31_resource.c
index 38c010afade1..cd3248dc31d8 100644
--- a/drivers/gpu/drm/amd/display/dc/dcn31/dcn31_resource.c
+++ b/drivers/gpu/drm/amd/display/dc/dcn31/dcn31_resource.c
@@ -1968,6 +1968,22 @@ static bool dcn31_resource_construct(
 	dc->caps.color.mpc.ogam_rom_caps.hlg = 0;
 	dc->caps.color.mpc.ocsc = 1;
 
+	/* read VBIOS LTTPR caps */
+	{
+		if (ctx->dc_bios->funcs->get_lttpr_caps) {
+			enum bp_result bp_query_result;
+			uint8_t is_vbios_lttpr_enable = 0;
+
+			bp_query_result = ctx->dc_bios->funcs->get_lttpr_caps(ctx->dc_bios, &is_vbios_lttpr_enable);
+			dc->caps.vbios_lttpr_enable = (bp_query_result == BP_RESULT_OK) && !!is_vbios_lttpr_enable;
+		}
+
+		/* interop bit is implicit */
+		{
+			dc->caps.vbios_lttpr_aware = true;
+		}
+	}
+
 	if (dc->ctx->dce_environment == DCE_ENV_PRODUCTION_DRV)
 		dc->debug = debug_defaults_drv;
 	else if (dc->ctx->dce_environment == DCE_ENV_FPGA_MAXIMUS) {