drm/amd/display: Add chip mask to HDMI retimer/redriver check

There were cases where the chip caps held additional bits that led to
the retimer/redriver check failing; use the proper mask to ensure that
we have only the bits that we care about for the check in question.
Signed-off-by: Andrew Jiang <Andrew.Jiang@amd.com>
Reviewed-by: Charlene Liu <Charlene.Liu@amd.com>
Reviewed-by: Tony Cheng <Tony.Cheng@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/core/dc_link.c

@@ -45,6 +45,7 @@
 #include "dce/dce_11_0_enum.h"
 #include "dce/dce_11_0_sh_mask.h"
 
+#define EXT_DISPLAY_PATH_CAPS__EXT_CHIP_MASK	0x007C /* Copied from atombios.h */
 #define LINK_INFO(...) \
 	dm_logger_write(dc_ctx->logger, LOG_HW_HOTPLUG, \
 		__VA_ARGS__)
@@ -1345,7 +1346,6 @@ static bool get_ext_hdmi_settings(struct pipe_ctx *pipe_ctx,
 					sizeof(integrated_info->dp2_ext_hdmi_6g_reg_settings));
 			result = true;
 			break;
-
 		default:
 			break;
 		}
@@ -1682,7 +1682,9 @@ static void enable_link_hdmi(struct pipe_ctx *pipe_ctx)
 		is_over_340mhz = true;
 
 	if (dc_is_hdmi_signal(pipe_ctx->stream->signal)) {
-		if ((pipe_ctx->stream->sink->link->chip_caps >> 2) == 0x2) {
+		unsigned short masked_chip_caps = pipe_ctx->stream->sink->link->chip_caps &
+				EXT_DISPLAY_PATH_CAPS__EXT_CHIP_MASK;
+		if (masked_chip_caps == (0x2 << 2)) {
 			/* DP159, Retimer settings */
 			eng_id = pipe_ctx->stream_res.stream_enc->id;
 
@@ -1693,7 +1695,7 @@ static void enable_link_hdmi(struct pipe_ctx *pipe_ctx)
 				write_i2c_default_retimer_setting(pipe_ctx,
 						is_vga_mode, is_over_340mhz);
 			}
-		} else if ((pipe_ctx->stream->sink->link->chip_caps >> 2) == 0x1) {
+		} else if (masked_chip_caps == (0x1 << 2)) {
 			/* PI3EQX1204, Redriver settings */
 			write_i2c_redriver_setting(pipe_ctx, is_over_340mhz);
 		}