linux-kernel - [PATCH AUTOSEL 5.19 28/29] drm/amd/display: increase dcn315 pstate change latency

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Date:   Sun,  2 Oct 2022 18:49:21 -0400
From:   Sasha Levin <sashal@...nel.org>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc:     Dmytro Laktyushkin <Dmytro.Laktyushkin@....com>,
        Jun Lei <Jun.Lei@....com>, Wayne Lin <wayne.lin@....com>,
        Daniel Wheeler <daniel.wheeler@....com>,
        Alex Deucher <alexander.deucher@....com>,
        Sasha Levin <sashal@...nel.org>, harry.wentland@....com,
        sunpeng.li@....com, Rodrigo.Siqueira@....com,
        christian.koenig@....com, Xinhui.Pan@....com, airlied@...il.com,
        daniel@...ll.ch, nicholas.kazlauskas@....com,
        qingqing.zhuo@....com, nikola.cornij@....com, paul.hsieh@....com,
        amd-gfx@...ts.freedesktop.org, dri-devel@...ts.freedesktop.org
Subject: [PATCH AUTOSEL 5.19 28/29] drm/amd/display: increase dcn315 pstate change latency

From: Dmytro Laktyushkin <Dmytro.Laktyushkin@....com>

[ Upstream commit dcc2527df918edfe297c5074ccc1f05eae361ca6 ]

[Why & How]
Update after new measurment came in

Reviewed-by: Jun Lei <Jun.Lei@....com>
Acked-by: Wayne Lin <wayne.lin@....com>
Signed-off-by: Dmytro Laktyushkin <Dmytro.Laktyushkin@....com>
Tested-by: Daniel Wheeler <daniel.wheeler@....com>
Signed-off-by: Alex Deucher <alexander.deucher@....com>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 .../dc/clk_mgr/dcn315/dcn315_clk_mgr.c        | 22 ++++++++++++-------
 1 file changed, 14 insertions(+), 8 deletions(-)

diff --git a/drivers/gpu/drm/amd/display/dc/clk_mgr/dcn315/dcn315_clk_mgr.c b/drivers/gpu/drm/amd/display/dc/clk_mgr/dcn315/dcn315_clk_mgr.c
index f4381725b210..c3d7712e9fd0 100644
--- a/drivers/gpu/drm/amd/display/dc/clk_mgr/dcn315/dcn315_clk_mgr.c
+++ b/drivers/gpu/drm/amd/display/dc/clk_mgr/dcn315/dcn315_clk_mgr.c
@@ -46,6 +46,9 @@
 #define TO_CLK_MGR_DCN315(clk_mgr)\
 	container_of(clk_mgr, struct clk_mgr_dcn315, base)
 
+#define UNSUPPORTED_DCFCLK 10000000
+#define MIN_DPP_DISP_CLK     100000
+
 static int dcn315_get_active_display_cnt_wa(
 		struct dc *dc,
 		struct dc_state *context)
@@ -146,6 +149,9 @@ static void dcn315_update_clocks(struct clk_mgr *clk_mgr_base,
 		}
 	}
 
+	/* Lock pstate by requesting unsupported dcfclk if change is unsupported */
+	if (!new_clocks->p_state_change_support)
+		new_clocks->dcfclk_khz = UNSUPPORTED_DCFCLK;
 	if (should_set_clock(safe_to_lower, new_clocks->dcfclk_khz, clk_mgr_base->clks.dcfclk_khz)) {
 		clk_mgr_base->clks.dcfclk_khz = new_clocks->dcfclk_khz;
 		dcn315_smu_set_hard_min_dcfclk(clk_mgr, clk_mgr_base->clks.dcfclk_khz);
@@ -159,10 +165,10 @@ static void dcn315_update_clocks(struct clk_mgr *clk_mgr_base,
 
 	// workaround: Limit dppclk to 100Mhz to avoid lower eDP panel switch to plus 4K monitor underflow.
 	if (!IS_DIAG_DC(dc->ctx->dce_environment)) {
-		if (new_clocks->dppclk_khz < 100000)
-			new_clocks->dppclk_khz = 100000;
-		if (new_clocks->dispclk_khz < 100000)
-			new_clocks->dispclk_khz = 100000;
+		if (new_clocks->dppclk_khz < MIN_DPP_DISP_CLK)
+			new_clocks->dppclk_khz = MIN_DPP_DISP_CLK;
+		if (new_clocks->dispclk_khz < MIN_DPP_DISP_CLK)
+			new_clocks->dispclk_khz = MIN_DPP_DISP_CLK;
 	}
 
 	if (should_set_clock(safe_to_lower, new_clocks->dppclk_khz, clk_mgr->base.clks.dppclk_khz)) {
@@ -272,7 +278,7 @@ static struct wm_table ddr5_wm_table = {
 		{
 			.wm_inst = WM_A,
 			.wm_type = WM_TYPE_PSTATE_CHG,
-			.pstate_latency_us = 64.0,
+			.pstate_latency_us = 129.0,
 			.sr_exit_time_us = 11.5,
 			.sr_enter_plus_exit_time_us = 14.5,
 			.valid = true,
@@ -280,7 +286,7 @@ static struct wm_table ddr5_wm_table = {
 		{
 			.wm_inst = WM_B,
 			.wm_type = WM_TYPE_PSTATE_CHG,
-			.pstate_latency_us = 64.0,
+			.pstate_latency_us = 129.0,
 			.sr_exit_time_us = 11.5,
 			.sr_enter_plus_exit_time_us = 14.5,
 			.valid = true,
@@ -288,7 +294,7 @@ static struct wm_table ddr5_wm_table = {
 		{
 			.wm_inst = WM_C,
 			.wm_type = WM_TYPE_PSTATE_CHG,
-			.pstate_latency_us = 64.0,
+			.pstate_latency_us = 129.0,
 			.sr_exit_time_us = 11.5,
 			.sr_enter_plus_exit_time_us = 14.5,
 			.valid = true,
@@ -296,7 +302,7 @@ static struct wm_table ddr5_wm_table = {
 		{
 			.wm_inst = WM_D,
 			.wm_type = WM_TYPE_PSTATE_CHG,
-			.pstate_latency_us = 64.0,
+			.pstate_latency_us = 129.0,
 			.sr_exit_time_us = 11.5,
 			.sr_enter_plus_exit_time_us = 14.5,
 			.valid = true,
-- 
2.35.1