drm/amd/display: workaround for hard hang on HPD on native DP

[Why]
HPD disable and enable sequences are not mutually exclusive
on Linux. For HPDs that spans over 1s (i.e. HPD low = 1s),
part of the disable sequence (specifically, a request to SMU
to lower refclk) could come right before the call to PHY
enable, causing DMUB to access an unresponsive PHY
and thus a hard hang on the system.

[How]
Disable 48mhz refclk off on native DP.

Reviewed-by: Hersen Wu <hersenxs.wu@amd.com>
Acked-by: Aurabindo Pillai <aurabindo.pillai@amd.com>
Signed-off-by: Qingqing Zhuo <qingqing.zhuo@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

diff --git a/drivers/gpu/drm/amd/display/dc/clk_mgr/dcn21/rn_clk_mgr.c b/drivers/gpu/drm/amd/display/dc/clk_mgr/dcn21/rn_clk_mgr.c
index c6f494f..6185f94 100644 (file)
--- a/drivers/gpu/drm/amd/display/dc/clk_mgr/dcn21/rn_clk_mgr.c
+++ b/drivers/gpu/drm/amd/display/dc/clk_mgr/dcn21/rn_clk_mgr.c
@@ -66,9 +66,11 @@ int rn_get_active_display_cnt_wa(
        for (i = 0; i < context->stream_count; i++) {
                const struct dc_stream_state *stream = context->streams[i];
 
+               /* Extend the WA to DP for Linux*/
                if (stream->signal == SIGNAL_TYPE_HDMI_TYPE_A ||
                                stream->signal == SIGNAL_TYPE_DVI_SINGLE_LINK ||
-                               stream->signal == SIGNAL_TYPE_DVI_DUAL_LINK)
+                               stream->signal == SIGNAL_TYPE_DVI_DUAL_LINK ||
+                               stream->signal == SIGNAL_TYPE_DISPLAY_PORT)
                        tmds_present = true;
        }