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From:   Sasha Levin <Alexander.Levin@microsoft.com>
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        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
CC:     Wesley Chalmers <Wesley.Chalmers@amd.com>,
        Eryk Brol <eryk.brol@amd.com>,
        Alex Deucher <alexander.deucher@amd.com>,
        Sasha Levin <Alexander.Levin@microsoft.com>
Subject: [PATCH AUTOSEL 4.18 026/136] drm/amd/display: fix use of
 uninitialized memory
Thread-Topic: [PATCH AUTOSEL 4.18 026/136] drm/amd/display: fix use of
 uninitialized memory
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Date:   Mon, 17 Sep 2018 03:00:27 +0000
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From: Wesley Chalmers <Wesley.Chalmers@amd.com>

[ Upstream commit f3e077d95ca0a016fdf3d6b1e97a9910dfdaff17 ]

DML does not calculate chroma values for RQ when surface is not YUV, but DC
will unconditionally use the uninitialized values for HW programming.
This does not cause visual corruption since HW will ignore garbage chroma
values when surface is not YUV, but causes presubmission tests to fail
golden value comparison.

Signed-off-by: Wesley Chalmers <Wesley.Chalmers@amd.com>
Signed-off-by: Eryk Brol <eryk.brol@amd.com>
Reviewed-by: Wenjing Liu <Wenjing.Liu@amd.com>
Acked-by: Harry Wentland <harry.wentland@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
---
 drivers/gpu/drm/amd/display/dc/dml/dml1_display_rq_dlg_calc.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/gpu/drm/amd/display/dc/dml/dml1_display_rq_dlg_calc.c =
b/drivers/gpu/drm/amd/display/dc/dml/dml1_display_rq_dlg_calc.c
index c2037daa8e66..0efbf411667a 100644
--- a/drivers/gpu/drm/amd/display/dc/dml/dml1_display_rq_dlg_calc.c
+++ b/drivers/gpu/drm/amd/display/dc/dml/dml1_display_rq_dlg_calc.c
@@ -239,6 +239,8 @@ void dml1_extract_rq_regs(
 	extract_rq_sizing_regs(mode_lib, &(rq_regs->rq_regs_l), rq_param.sizing.r=
q_l);
 	if (rq_param.yuv420)
 		extract_rq_sizing_regs(mode_lib, &(rq_regs->rq_regs_c), rq_param.sizing.=
rq_c);
+	else
+		memset(&(rq_regs->rq_regs_c), 0, sizeof(rq_regs->rq_regs_c));
=20
 	rq_regs->rq_regs_l.swath_height =3D dml_log2(rq_param.dlg.rq_l.swath_heig=
ht);
 	rq_regs->rq_regs_c.swath_height =3D dml_log2(rq_param.dlg.rq_c.swath_heig=
ht);
--=20
2.17.1