From:   Sasha Levin <sashal@kernel.org>
To:     linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc:     Daniel Miess <Daniel.Miess@amd.com>,
        Nicholas Kazlauskas <Nicholas.Kazlauskas@amd.com>,
        Alex Hung <alex.hung@amd.com>,
        Daniel Wheeler <daniel.wheeler@amd.com>,
        Alex Deucher <alexander.deucher@amd.com>,
        Sasha Levin <sashal@kernel.org>, harry.wentland@amd.com,
        sunpeng.li@amd.com, Rodrigo.Siqueira@amd.com,
        christian.koenig@amd.com, Xinhui.Pan@amd.com, airlied@gmail.com,
        daniel@ffwll.ch, nicholas.kazlauskas@amd.com, Charlene.Liu@amd.com,
        sancchen@amd.com, mwen@igalia.com, amd-gfx@lists.freedesktop.org,
        dri-devel@lists.freedesktop.org
Subject: [PATCH AUTOSEL 6.1 30/38] drm/amd/display: Adjust downscaling limits for dcn314
Date:   Thu,  9 Feb 2023 06:14:49 -0500
Message-Id: <20230209111459.1891941-30-sashal@kernel.org>
In-Reply-To: <20230209111459.1891941-1-sashal@kernel.org>
References: <20230209111459.1891941-1-sashal@kernel.org>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

From: Daniel Miess <Daniel.Miess@amd.com>

[ Upstream commit dd2db2dc4bd298f33dea50c80c3c11bee4e3b0a4 ]

[Why]
Lower max_downscale_ratio and ARGB888 downscale factor
to prevent cases where underflow may occur on dcn314

[How]
Set max_downscale_ratio to 400 and ARGB downscale factor
to 250 for dcn314

Reviewed-by: Nicholas Kazlauskas <Nicholas.Kazlauskas@amd.com>
Acked-by: Alex Hung <alex.hung@amd.com>
Signed-off-by: Daniel Miess <Daniel.Miess@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/gpu/drm/amd/display/dc/dcn314/dcn314_resource.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/amd/display/dc/dcn314/dcn314_resource.c b/drivers/gpu/drm/amd/display/dc/dcn314/dcn314_resource.c
index 9066c511a0529..c80c8c8f51e97 100644
--- a/drivers/gpu/drm/amd/display/dc/dcn314/dcn314_resource.c
+++ b/drivers/gpu/drm/amd/display/dc/dcn314/dcn314_resource.c
@@ -871,8 +871,9 @@ static const struct dc_plane_cap plane_cap = {
 	},
 
 	// 6:1 downscaling ratio: 1000/6 = 166.666
+	// 4:1 downscaling ratio for ARGB888 to prevent underflow during P010 playback: 1000/4 = 250
 	.max_downscale_factor = {
-			.argb8888 = 167,
+			.argb8888 = 250,
 			.nv12 = 167,
 			.fp16 = 167
 	},
@@ -1755,7 +1756,7 @@ static bool dcn314_resource_construct(
 	pool->base.underlay_pipe_index = NO_UNDERLAY_PIPE;
 	pool->base.pipe_count = pool->base.res_cap->num_timing_generator;
 	pool->base.mpcc_count = pool->base.res_cap->num_timing_generator;
-	dc->caps.max_downscale_ratio = 600;
+	dc->caps.max_downscale_ratio = 400;
 	dc->caps.i2c_speed_in_khz = 100;
 	dc->caps.i2c_speed_in_khz_hdcp = 100;
 	dc->caps.max_cursor_size = 256;
-- 
2.39.0