From 9470620e99e90999dc367bdcccc7e1274dcbb796 Mon Sep 17 00:00:00 2001
From: Nicholas Kazlauskas <nicholas.kazlauskas@amd.com>
Date: Tue, 5 Oct 2021 10:55:57 -0400
Subject: [PATCH] drm/amd/display: Enable PSR by default on newer DCN
Git-commit: 9470620e99e90999dc367bdcccc7e1274dcbb796
Patch-mainline: v5.16-rc1
References: git-fixes

[ backport note: rewritten the IP_VERSION check with the old asic_type
  check -- tiwai ]

[Why]
For optimal power savings on panels that can support it.

This was previously left disabled by default because of issues with
compositors that do not pageflip and scan out directly to the
frontbuffer.

For these compositors we now have detection methods that wait for x
number of pageflips after a full update - triggered by a buffer or
format change typically.

This may introduce bugs or new cases not tested by users so this is
only currently targeting newer DCN.

[How]
Add code in DM to set PSR state by default for newer DCN while falling
back to the feature mask for older.

Add a global debug flag that can be set to disable it for either.

Signed-off-by: Nicholas Kazlauskas <nicholas.kazlauskas@amd.com>
Reviewed-by: Harry Wentland <harry.wentland@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Acked-by: Takashi Iwai <tiwai@suse.de>

---
 drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c |   16 +++++++++++++++-
 drivers/gpu/drm/amd/include/amd_shared.h          |    5 +++--
 2 files changed, 18 insertions(+), 3 deletions(-)

--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
@@ -3768,6 +3768,7 @@ static int amdgpu_dm_initialize_drm_devi
 	int32_t primary_planes;
 	enum dc_connection_type new_connection_type = dc_connection_none;
 	const struct dc_plane_cap *plane;
+	bool psr_feature_enabled = false;
 
 	dm->display_indexes_num = dm->dc->caps.max_streams;
 	/* Update the actual used number of crtc */
@@ -3849,6 +3850,18 @@ static int amdgpu_dm_initialize_drm_devi
 	default:
 		DRM_DEBUG_KMS("Unsupported ASIC type for outbox: 0x%X\n", adev->asic_type);
 	}
+
+	/* Determine whether to enable PSR support by default. */
+	if (!(amdgpu_dc_debug_mask & DC_DISABLE_PSR)) {
+		switch (adev->asic_type) {
+		case CHIP_YELLOW_CARP:
+			psr_feature_enabled = true;
+			break;
+		default:
+			psr_feature_enabled = amdgpu_dc_feature_mask & DC_PSR_MASK;
+			break;
+		}
+	}
 #endif
 
 	/* loops over all connectors on the board */
@@ -3892,7 +3905,8 @@ static int amdgpu_dm_initialize_drm_devi
 		} else if (dc_link_detect(link, DETECT_REASON_BOOT)) {
 			amdgpu_dm_update_connector_after_detect(aconnector);
 			register_backlight_device(dm, link);
-			if (amdgpu_dc_feature_mask & DC_PSR_MASK)
+
+			if (psr_feature_enabled)
 				amdgpu_dm_set_psr_caps(link);
 		}
 
--- a/drivers/gpu/drm/amd/include/amd_shared.h
+++ b/drivers/gpu/drm/amd/include/amd_shared.h
@@ -228,7 +228,7 @@ enum DC_FEATURE_MASK {
 	DC_FBC_MASK = (1 << 0), //0x1, disabled by default
 	DC_MULTI_MON_PP_MCLK_SWITCH_MASK = (1 << 1), //0x2, enabled by default
 	DC_DISABLE_FRACTIONAL_PWM_MASK = (1 << 2), //0x4, disabled by default
-	DC_PSR_MASK = (1 << 3), //0x8, disabled by default
+	DC_PSR_MASK = (1 << 3), //0x8, disabled by default for dcn < 3.1
 	DC_EDP_NO_POWER_SEQUENCING = (1 << 4), //0x10, disabled by default
 };
 
@@ -236,7 +236,8 @@ enum DC_DEBUG_MASK {
 	DC_DISABLE_PIPE_SPLIT = 0x1,
 	DC_DISABLE_STUTTER = 0x2,
 	DC_DISABLE_DSC = 0x4,
-	DC_DISABLE_CLOCK_GATING = 0x8
+	DC_DISABLE_CLOCK_GATING = 0x8,
+	DC_DISABLE_PSR = 0x10,
 };
 
 enum amd_dpm_forced_level;