drm/amd/display: Don't compare dppclk before updating DTO

[Why]
In dcn3_update_clocks there are situations where dppclk is not
lowered (i.e. stays the same), but DTO still needs to be increased
before we program pipe frontend (i.e. in prepare_bandwidth). If we
don't program the new DTO value before we program the pipe,
we will underflow as soon as the pipe lock is released until the
next call to dcn3_update_clocks where the DTO is updated.

[How]
Remove dppclk check before programming new DTO value.

Signed-off-by: Alvin Lee <alvin.lee2@amd.com>
Reviewed-by: Jun Lei <Jun.Lei@amd.com>
Acked-by: Eryk Brol <eryk.brol@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

diff --git a/drivers/gpu/drm/amd/display/dc/clk_mgr/dcn30/dcn30_clk_mgr.c b/drivers/gpu/drm/amd/display/dc/clk_mgr/dcn30/dcn30_clk_mgr.c
index d94fdc52be374a0386b60da05803ea03d0022bf2..9133646f6d5f0b29714d55d6c4ef37828531e8cc 100644 (file)
--- a/drivers/gpu/drm/amd/display/dc/clk_mgr/dcn30/dcn30_clk_mgr.c
+++ b/drivers/gpu/drm/amd/display/dc/clk_mgr/dcn30/dcn30_clk_mgr.c
@@ -323,9 +323,10 @@ static void dcn3_update_clocks(struct clk_mgr *clk_mgr_base,
                        /* if clock is being raised, increase refclk before lowering DTO */
                        if (update_dppclk || update_dispclk)
                                dcn20_update_clocks_update_dentist(clk_mgr);
-                       /* always update dtos unless clock is lowered and not safe to lower */
-                       if (new_clocks->dppclk_khz >= dc->current_state->bw_ctx.bw.dcn.clk.dppclk_khz)
-                               dcn20_update_clocks_update_dpp_dto(clk_mgr, context, safe_to_lower);
+                       /* There is a check inside dcn20_update_clocks_update_dpp_dto which ensures
+                        * that we do not lower dto when it is not safe to lower. We do not need to
+                        * compare the current and new dppclk before calling this function.*/
+                       dcn20_update_clocks_update_dpp_dto(clk_mgr, context, safe_to_lower);
                }
        }