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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Evan Quan <evan.quan@amd.com>,
        Ahzo <Ahzo@tutanota.com>,
        Alex Deucher <alexander.deucher@amd.com>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 4.19 141/211] drm/amd/powerplay/smu7: enforce minimal VBITimeout (v2)
Date:   Thu,  3 Oct 2019 17:53:27 +0200
Message-Id: <20191003154519.506509425@linuxfoundation.org>
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From: Ahzo <Ahzo@tutanota.com>

[ Upstream commit f659bb6dae58c113805f92822e4c16ddd3156b79 ]

This fixes screen corruption/flickering on 75 Hz displays.

v2: make print statement debug only (Alex)

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=102646
Reviewed-by: Evan Quan <evan.quan@amd.com>
Signed-off-by: Ahzo <Ahzo@tutanota.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/gpu/drm/amd/powerplay/hwmgr/smu7_hwmgr.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/drivers/gpu/drm/amd/powerplay/hwmgr/smu7_hwmgr.c b/drivers/gpu/drm/amd/powerplay/hwmgr/smu7_hwmgr.c
index b52ccab428a9e..c7c505095402d 100644
--- a/drivers/gpu/drm/amd/powerplay/hwmgr/smu7_hwmgr.c
+++ b/drivers/gpu/drm/amd/powerplay/hwmgr/smu7_hwmgr.c
@@ -4052,6 +4052,11 @@ static int smu7_program_display_gap(struct pp_hwmgr *hwmgr)
 
 	data->frame_time_x2 = frame_time_in_us * 2 / 100;
 
+	if (data->frame_time_x2 < 280) {
+		pr_debug("%s: enforce minimal VBITimeout: %d -> 280\n", __func__, data->frame_time_x2);
+		data->frame_time_x2 = 280;
+	}
+
 	display_gap2 = pre_vbi_time_in_us * (ref_clock / 100);
 
 	cgs_write_ind_register(hwmgr->device, CGS_IND_REG__SMC, ixCG_DISPLAY_GAP_CNTL2, display_gap2);
-- 
2.20.1