drm/amd/display: add option to disable DCC for DCC 128b request

1. reverts commit e67f51012740 ("dc: temp disable DCC on high res.")
- default still DCC enabled

2. add debug options to decide how DCC is disabled
- disable DCC
- disable DCC if DCC requires 128b (aka. half) request
-- observed compressed data corruption result in screen corruption in
full (256b) request while half (128b) would cause DCN to hang, result in
DF hang

Signed-off-by: Tony Cheng <tony.cheng@amd.com>
Reviewed-by: Yongqiang Sun <yongqiang.sun@amd.com>
Acked-by: Harry Wentland <Harry.Wentland@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/display/dc/dc.h

@@ -56,11 +56,10 @@ struct dc_caps {
 	uint32_t max_planes;
 	uint32_t max_downscale_ratio;
 	uint32_t i2c_speed_in_khz;
-
 	unsigned int max_cursor_size;
+	bool dcc_const_color;
 };
 
-
 struct dc_dcc_surface_param {
 	struct dc_size surface_size;
 	enum surface_pixel_format format;
@@ -162,6 +161,12 @@ struct dc_config {
 	bool disable_disp_pll_sharing;
 };
 
+enum dcc_option {
+	DCC_ENABLE = 0,
+	DCC_DISABLE = 1,
+	DCC_HALF_REQ_DISALBE = 2,
+};
+
 enum pipe_split_policy {
 	MPC_SPLIT_DYNAMIC = 0,
 	MPC_SPLIT_AVOID = 1,
@@ -177,7 +182,7 @@ struct dc_debug {
 	bool clock_trace;
 	bool validation_trace;
 	bool disable_stutter;
-	bool disable_dcc;
+	enum dcc_option disable_dcc;
 	bool disable_dfs_bypass;
 	bool disable_dpp_power_gate;
 	bool disable_hubp_power_gate;

drivers/gpu/drm/amd/display/dc/dcn10/dcn10_resource.c

@@ -414,7 +414,6 @@ static const struct resource_caps res_cap = {
 };
 
 static const struct dc_debug debug_defaults_drv = {
-		.disable_dcc = false,
 		.sanity_checks = true,
 		.disable_dmcu = true,
 		.force_abm_enable = false,
@@ -428,6 +427,7 @@ static const struct dc_debug debug_defaults_drv = {
 		.use_dml_wm = false,
 
 		.pipe_split_policy = MPC_SPLIT_AVOID_MULT_DISP,
+		.disable_dcc = DCC_ENABLE,
 };
 
 static const struct dc_debug debug_defaults_diags = {
@@ -1080,7 +1080,7 @@ static bool get_dcc_compression_cap(const struct dc *dc,
 
 	memset(output, 0, sizeof(*output));
 
-	if (dc->debug.disable_dcc)
+	if (dc->debug.disable_dcc == DCC_DISABLE)
 		return false;
 
 	if (!dcc_support_pixel_format(input->format,
@@ -1124,32 +1124,30 @@ static bool get_dcc_compression_cap(const struct dc *dc,
 			dcc_control = dcc_control__128_128_xxx;
 	}
 
+	if (dc->debug.disable_dcc == DCC_HALF_REQ_DISALBE &&
+		dcc_control != dcc_control__256_256_xxx)
+		return false;
+
 	switch (dcc_control) {
 	case dcc_control__256_256_xxx:
 		output->grph.rgb.max_uncompressed_blk_size = 256;
 		output->grph.rgb.max_compressed_blk_size = 256;
 		output->grph.rgb.independent_64b_blks = false;
-		output->capable = true;
-		output->const_color_support = false;
 		break;
 	case dcc_control__128_128_xxx:
 		output->grph.rgb.max_uncompressed_blk_size = 128;
 		output->grph.rgb.max_compressed_blk_size = 128;
 		output->grph.rgb.independent_64b_blks = false;
-		/*temp: not allow dcc on high res*/
-		output->capable = false;
-		output->const_color_support = false;
 		break;
 	case dcc_control__256_64_64:
 		output->grph.rgb.max_uncompressed_blk_size = 256;
 		output->grph.rgb.max_compressed_blk_size = 64;
 		output->grph.rgb.independent_64b_blks = true;
-		/*temp: not allow dcc on high res*/
-		output->capable = false;
-		output->const_color_support = false;
 		break;
 	}
 
+	output->capable = true;
+	output->const_color_support = false;
 
 	return true;
 }