[13/25] drm/amd/display: Do not double-buffer DTO adjustments

Submitted by Li, Sun peng (Leo) on Sept. 10, 2019, 1:54 p.m.

Details

Message ID 20190910135445.18300-14-sunpeng.li@amd.com
State New
Headers show
Series "DC Patches 09 Sep 2019" ( rev: 1 ) in AMD X.Org drivers

Not browsing as part of any series.

Commit Message

Li, Sun peng (Leo) Sept. 10, 2019, 1:54 p.m.
From: Wesley Chalmers <Wesley.Chalmers@amd.com>

[WHY]
When changing DPP global ref clock, DTO adjustments must take effect
immediately, or else underflow may occur.
It appears the original decision to double-buffer DTO adjustments was made to
prevent underflows that occur when raising DPP ref clock (which is not
double-buffered), but that same decision causes similar issues when
lowering DPP global ref clock. The better solution is to order the
adjustments according to whether clocks are being raised or lowered.

Signed-off-by: Wesley Chalmers <Wesley.Chalmers@amd.com>
Reviewed-by: Dmytro Laktyushkin <Dmytro.Laktyushkin@amd.com>
Acked-by: Anthony Koo <Anthony.Koo@amd.com>
Acked-by: Leo Li <sunpeng.li@amd.com>
---
 .../gpu/drm/amd/display/dc/dcn20/dcn20_dccg.c | 21 -------------------
 1 file changed, 21 deletions(-)

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diff --git a/drivers/gpu/drm/amd/display/dc/dcn20/dcn20_dccg.c b/drivers/gpu/drm/amd/display/dc/dcn20/dcn20_dccg.c
index f9b99f8cfc31..313d3793005e 100644
--- a/drivers/gpu/drm/amd/display/dc/dcn20/dcn20_dccg.c
+++ b/drivers/gpu/drm/amd/display/dc/dcn20/dcn20_dccg.c
@@ -117,27 +117,6 @@  void dccg2_get_dccg_ref_freq(struct dccg *dccg,
 
 void dccg2_init(struct dccg *dccg)
 {
-	struct dcn_dccg *dccg_dcn = TO_DCN_DCCG(dccg);
-
-	// Fallthrough intentional to program all available dpp_dto's
-	switch (dccg_dcn->base.ctx->dc->res_pool->pipe_count) {
-	case 6:
-		REG_UPDATE(DPPCLK_DTO_CTRL, DPPCLK_DTO_DB_EN[5], 1);
-	case 5:
-		REG_UPDATE(DPPCLK_DTO_CTRL, DPPCLK_DTO_DB_EN[4], 1);
-	case 4:
-		REG_UPDATE(DPPCLK_DTO_CTRL, DPPCLK_DTO_DB_EN[3], 1);
-	case 3:
-		REG_UPDATE(DPPCLK_DTO_CTRL, DPPCLK_DTO_DB_EN[2], 1);
-	case 2:
-		REG_UPDATE(DPPCLK_DTO_CTRL, DPPCLK_DTO_DB_EN[1], 1);
-	case 1:
-		REG_UPDATE(DPPCLK_DTO_CTRL, DPPCLK_DTO_DB_EN[0], 1);
-		break;
-	default:
-		ASSERT(false);
-		break;
-	}
 }
 
 static const struct dccg_funcs dccg2_funcs = {