From 481f576c6c21bf0446eaa23623ef0262e9a5387c Mon Sep 17 00:00:00 2001
From: Nicholas Kazlauskas <nicholas.kazlauskas@amd.com>
Date: Wed, 12 Sep 2018 08:55:42 -0400
Subject: drm/amd/display: Raise dispclk value for dce120 by 15%
Git-commit: 481f576c6c21bf0446eaa23623ef0262e9a5387c
Patch-mainline: v4.20-rc1
References: bsc#1113956
[Why]
The DISPCLK value was previously requested to be 15% higher for all
ASICs that went through the dce110 bandwidth code path. As part of a
refactoring of dce_clocks and the dce110 set bandwidth codepath this
was removed for power saving considerations.
That change caused display corruption under certain hardware
configurations with Vega10.
[How]
The 15% DISPCLK increase is brought back but only on dce110 for now.
This is should be a temporary workaround until the root cause is sorted
out for why this occurs on Vega (or other ASICs, if reported).
Tested-by: Nick Sarnie <sarnex@gentoo.org>
Signed-off-by: Nicholas Kazlauskas <nicholas.kazlauskas@amd.com>
Reviewed-by: Harry Wentland <Harry.Wentland@amd.com>
Acked-by: Bhawanpreet Lakha <Bhawanpreet.Lakha@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Acked-by: Thomas Zimmermann <tzimmermann@suse.de>
---
drivers/gpu/drm/amd/display/dc/dce/dce_clocks.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/drivers/gpu/drm/amd/display/dc/dce/dce_clocks.c b/drivers/gpu/drm/amd/display/dc/dce/dce_clocks.c
index bf6261a1584b..d42afa081452 100644
--- a/drivers/gpu/drm/amd/display/dc/dce/dce_clocks.c
+++ b/drivers/gpu/drm/amd/display/dc/dce/dce_clocks.c
@@ -468,6 +468,9 @@ static void dce12_update_clocks(struct dccg *dccg,
{
struct dm_pp_clock_for_voltage_req clock_voltage_req = {0};
+ /* TODO: Investigate why this is needed to fix display corruption. */
+ new_clocks->dispclk_khz = new_clocks->dispclk_khz * 115 / 100;
+
if (should_set_clock(safe_to_lower, new_clocks->dispclk_khz, dccg->clks.dispclk_khz)) {
clock_voltage_req.clk_type = DM_PP_CLOCK_TYPE_DISPLAY_CLK;
clock_voltage_req.clocks_in_khz = new_clocks->dispclk_khz;
--
2.20.1