drm/amd/display: take ODM slice count into account when deciding DSC slice

[why]
DSC slice must be divisible by ODM slice count.

[how]
If DSC slice count is not a multiple of ODM slice count, increase DSC
slice until it is. Otherwise fail to compute DSC configuration.
Reviewed-by: Chaitanya Dhere <chaitanya.dhere@amd.com>
Acked-by: Wayne Lin <wayne.lin@amd.com>
Signed-off-by: Wenjing Liu <wenjing.liu@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/display/dc/dsc/dc_dsc.c

@@ -922,14 +922,30 @@ static bool setup_dsc_config(
 		else
 			is_dsc_possible = false;
 	}
-	// When we force 2:1 ODM, we can't have 1 slice to divide amongst 2 separate DSC instances
-	// need to enforce at minimum 2 horizontal slices
-	if (options->dsc_force_odm_hslice_override) {
-		num_slices_h = fit_num_slices_up(dsc_common_caps.slice_caps, 2);
-		if (num_slices_h == 0)
-			is_dsc_possible = false;
+	// When we force ODM, num dsc h slices must be divisible by num odm h slices
+	switch (options->dsc_force_odm_hslice_override) {
+	case 0:
+	case 1:
+		break;
+	case 2:
+		if (num_slices_h < 2)
+			num_slices_h = fit_num_slices_up(dsc_common_caps.slice_caps, 2);
+		break;
+	case 3:
+		if (dsc_common_caps.slice_caps.bits.NUM_SLICES_12)
+			num_slices_h = 12;
+		else
+			num_slices_h = 0;
+		break;
+	case 4:
+		if (num_slices_h < 4)
+			num_slices_h = fit_num_slices_up(dsc_common_caps.slice_caps, 4);
+		break;
+	default:
+		break;
 	}
-
+	if (num_slices_h == 0)
+		is_dsc_possible = false;
 	if (!is_dsc_possible)
 		goto done;