drm/amd/display: fix use_max_lb flag for 420 pixel formats

stable inclusion
from stable-5.10.51
commit 3ca86d44b9023cd96c893d6dd90aacbca90e4d74
bugzilla: 175263 https://gitee.com/openeuler/kernel/issues/I4DT6F

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=3ca86d44b9023cd96c893d6dd90aacbca90e4d74

--------------------------------

[ Upstream commit 8809a7a4 ]

Right now the flag simply selects memory config 0 when flag is true
however 420 modes benefit more from memory config 3.
Signed-off-by: NDmytro Laktyushkin <Dmytro.Laktyushkin@amd.com>
Reviewed-by: NAric Cyr <Aric.Cyr@amd.com>
Acked-by: NStylon Wang <stylon.wang@amd.com>
Tested-by: NDaniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>
Signed-off-by: NSasha Levin <sashal@kernel.org>
Signed-off-by: NChen Jun <chenjun102@huawei.com>
Acked-by: NWeilong Chen <chenweilong@huawei.com>
Signed-off-by: NChen Jun <chenjun102@huawei.com>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>

drivers/gpu/drm/amd/display/dc/dcn10/dcn10_dpp_dscl.c

@@ -482,10 +482,13 @@ static enum lb_memory_config dpp1_dscl_find_lb_memory_config(struct dcn10_dpp *d
 	int vtaps_c = scl_data->taps.v_taps_c;
 	int ceil_vratio = dc_fixpt_ceil(scl_data->ratios.vert);
 	int ceil_vratio_c = dc_fixpt_ceil(scl_data->ratios.vert_c);
-	enum lb_memory_config mem_cfg = LB_MEMORY_CONFIG_0;
 
-	if (dpp->base.ctx->dc->debug.use_max_lb)
-		return mem_cfg;
+	if (dpp->base.ctx->dc->debug.use_max_lb) {
+		if (scl_data->format == PIXEL_FORMAT_420BPP8
+				|| scl_data->format == PIXEL_FORMAT_420BPP10)
+			return LB_MEMORY_CONFIG_3;
+		return LB_MEMORY_CONFIG_0;
+	}
 
 	dpp->base.caps->dscl_calc_lb_num_partitions(
 			scl_data, LB_MEMORY_CONFIG_1, &num_part_y, &num_part_c);