drm/amd/display: Adjust downscaling limits for dcn314

[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>

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 f9ea1e8..79850a6 100644 (file)
--- a/drivers/gpu/drm/amd/display/dc/dcn314/dcn314_resource.c
+++ b/drivers/gpu/drm/amd/display/dc/dcn314/dcn314_resource.c
@@ -874,8 +874,9 @@ 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
        },
@@ -1763,7 +1764,7 @@ 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;