drm/amd/display: fixed dcn30+ underflow issue

[ Upstream commit 37403ce ]

[Why]
Observing underflow on dcn30+ system config at 4k144hz

[How]
We set the UCLK hardmax on AC/DC switch if softmax is enabled
and also on boot. While booting up the UCLK Hardmax is set
to softmax before the init sequence and the init sequence
resets the hardmax to UCLK max which enables P-state switching.
Just added a conditional check to avoid setting hardmax on init.

Reviewed-by: Alvin Lee <Alvin.Lee2@amd.com>
Reviewed-by: Martin Leung <Martin.Leung@amd.com>
Acked-by: Qingqing Zhuo <qingqing.zhuo@amd.com>
Signed-off-by: Ayush Gupta <ayugupta@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

Author: Ayush Gupta

drivers/gpu/drm/amd/display/dc/dcn30/dcn30_hwseq.c

@@ -629,7 +629,8 @@ void dcn30_init_hw(struct dc *dc)
 	if (dc->clk_mgr->funcs->notify_wm_ranges)
 		dc->clk_mgr->funcs->notify_wm_ranges(dc->clk_mgr);
 
-	if (dc->clk_mgr->funcs->set_hard_max_memclk)
+	//if softmax is enabled then hardmax will be set by a different call
+	if (dc->clk_mgr->funcs->set_hard_max_memclk && !dc->clk_mgr->dc_mode_softmax_enabled)
 		dc->clk_mgr->funcs->set_hard_max_memclk(dc->clk_mgr);
 
 	if (dc->res_pool->hubbub->funcs->force_pstate_change_control)

drivers/gpu/drm/amd/display/dc/dcn31/dcn31_hwseq.c

@@ -284,7 +284,7 @@ void dcn31_init_hw(struct dc *dc)
 	if (dc->clk_mgr->funcs->notify_wm_ranges)
 		dc->clk_mgr->funcs->notify_wm_ranges(dc->clk_mgr);
 
-	if (dc->clk_mgr->funcs->set_hard_max_memclk)
+	if (dc->clk_mgr->funcs->set_hard_max_memclk && !dc->clk_mgr->dc_mode_softmax_enabled)
 		dc->clk_mgr->funcs->set_hard_max_memclk(dc->clk_mgr);
 
 	if (dc->res_pool->hubbub->funcs->force_pstate_change_control)

drivers/gpu/drm/amd/display/dc/dcn32/dcn32_hwseq.c

@@ -970,7 +970,7 @@ void dcn32_init_hw(struct dc *dc)
 	if (dc->clk_mgr->funcs->notify_wm_ranges)
 		dc->clk_mgr->funcs->notify_wm_ranges(dc->clk_mgr);
 
-	if (dc->clk_mgr->funcs->set_hard_max_memclk)
+	if (dc->clk_mgr->funcs->set_hard_max_memclk && !dc->clk_mgr->dc_mode_softmax_enabled)
 		dc->clk_mgr->funcs->set_hard_max_memclk(dc->clk_mgr);
 
 	if (dc->res_pool->hubbub->funcs->force_pstate_change_control)