[PATCH] drm/amd/powerplay: fix possible hang with 3+ 4K monitors

[Evan Quan]

If DAL requires to force MCLK high, the FCLK will be
forced to high also.

Change-Id: Iaff8956ca1faafaf904f0bec108f566e8bbf6a64
Signed-off-by: Evan Quan <evan.quan at amd.com>
---
 drivers/gpu/drm/amd/powerplay/hwmgr/vega20_hwmgr.c | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/amd/powerplay/hwmgr/vega20_hwmgr.c b/drivers/gpu/drm/amd/powerplay/hwmgr/vega20_hwmgr.c
index 3f349ada8de0..38dbec3caa01 100644
--- a/drivers/gpu/drm/amd/powerplay/hwmgr/vega20_hwmgr.c
+++ b/drivers/gpu/drm/amd/powerplay/hwmgr/vega20_hwmgr.c
@@ -3471,6 +3471,7 @@ static int vega20_apply_clocks_adjust_rules(struct pp_hwmgr *hwmgr)
 	struct vega20_single_dpm_table *dpm_table;
 	bool vblank_too_short = false;
 	bool disable_mclk_switching;
+	bool disable_fclk_switching;
 	uint32_t i, latency;
 
 	disable_mclk_switching = ((1 < hwmgr->display_config->num_display) &&
@@ -3546,13 +3547,20 @@ static int vega20_apply_clocks_adjust_rules(struct pp_hwmgr *hwmgr)
 	if (hwmgr->display_config->nb_pstate_switch_disable)
 		dpm_table->dpm_state.hard_min_level = dpm_table->dpm_levels[dpm_table->count - 1].value;
 
+	if ((disable_mclk_switching &&
+	    (dpm_table->dpm_state.hard_min_level == dpm_table->dpm_levels[dpm_table->count - 1].value)) ||
+	     hwmgr->display_config->min_mem_set_clock / 100 >= dpm_table->dpm_levels[dpm_table->count - 1].value)
+		disable_fclk_switching = true;
+	else
+		disable_fclk_switching = false;
+
 	/* fclk */
 	dpm_table = &(data->dpm_table.fclk_table);
 	dpm_table->dpm_state.soft_min_level = dpm_table->dpm_levels[0].value;
 	dpm_table->dpm_state.soft_max_level = VG20_CLOCK_MAX_DEFAULT;
 	dpm_table->dpm_state.hard_min_level = dpm_table->dpm_levels[0].value;
 	dpm_table->dpm_state.hard_max_level = VG20_CLOCK_MAX_DEFAULT;
-	if (hwmgr->display_config->nb_pstate_switch_disable)
+	if (hwmgr->display_config->nb_pstate_switch_disable || disable_fclk_switching)
 		dpm_table->dpm_state.soft_min_level = dpm_table->dpm_levels[dpm_table->count - 1].value;
 
 	/* vclk */
-- 
2.21.0