Revert "drm/amd/display: disable SubVP + DRR to prevent underflow"

This reverts commit 80c6d680.
The orignal commit was intended as a workaround to prevent underflow and
flickering when using one normal monitor and the other high refresh rate
monitor (> 120Hz).

This patch is being reverted in favour of a software solution to enable
SubVP+DRR
Signed-off-by: Aurabindo Pillai <aurabindo.pillai@amd.com>
Reviewed-by: Rodrigo Siqueira <Rodrigo.Siqueira@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c

@@ -1646,11 +1646,6 @@ static int amdgpu_dm_init(struct amdgpu_device *adev)
 	if (amdgpu_dc_feature_mask & DC_DISABLE_LTTPR_DP2_0)
 		init_data.flags.allow_lttpr_non_transparent_mode.bits.DP2_0 = true;
 
-	/* Disable SubVP + DRR config by default */
-	init_data.flags.disable_subvp_drr = true;
-	if (amdgpu_dc_feature_mask & DC_ENABLE_SUBVP_DRR)
-		init_data.flags.disable_subvp_drr = false;
-
 	init_data.flags.seamless_boot_edp_requested = false;
 
 	if (check_seamless_boot_capability(adev)) {

drivers/gpu/drm/amd/display/dc/dml/dcn32/dcn32_fpu.c

@@ -892,10 +892,6 @@ static bool subvp_drr_schedulable(struct dc *dc, struct dc_state *context, struc
 	int16_t stretched_drr_us = 0;
 	int16_t drr_stretched_vblank_us = 0;
 	int16_t max_vblank_mallregion = 0;
-	const struct dc_config *config = &dc->config;
-
-	if (config->disable_subvp_drr)
-		return false;
 
 	// Find SubVP pipe
 	for (i = 0; i < dc->res_pool->pipe_count; i++) {

drivers/gpu/drm/amd/include/amd_shared.h

@@ -240,7 +240,6 @@ enum DC_FEATURE_MASK {
 	DC_DISABLE_LTTPR_DP2_0 = (1 << 6), //0x40, disabled by default
 	DC_PSR_ALLOW_SMU_OPT = (1 << 7), //0x80, disabled by default
 	DC_PSR_ALLOW_MULTI_DISP_OPT = (1 << 8), //0x100, disabled by default
-	DC_ENABLE_SUBVP_DRR = (1 << 9), // 0x200, disabled by default
 };
 
 enum DC_DEBUG_MASK {