[PATCH 14/16] drm/amd/display: Update dram_clock_change_latency for DCN2.1

Anson Jacob Anson.Jacob at amd.com
Fri Jan 15 17:27:16 UTC 2021


From: Jake Wang <haonan.wang2 at amd.com>

[WHY]
dram clock change latencies get updated using ddr4 latency table, but
that update does not happen before validation. This value
should not be the default and should be number received from
df for better mode support.
This may cause a PState hang on high refresh panels with short vblanks
such as on 1080p 360hz or 300hz panels.

[HOW]
Update latency from 23.84 to 11.72.

Signed-off-by: Jake Wang <haonan.wang2 at amd.com>
Reviewed-by: Sung Lee <Sung.Lee at amd.com>
Acked-by: Anson Jacob <anson.jacob at amd.com>
---
 drivers/gpu/drm/amd/display/dc/dcn21/dcn21_resource.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/amd/display/dc/dcn21/dcn21_resource.c b/drivers/gpu/drm/amd/display/dc/dcn21/dcn21_resource.c
index 1c88d2edd381..b000b43a820d 100644
--- a/drivers/gpu/drm/amd/display/dc/dcn21/dcn21_resource.c
+++ b/drivers/gpu/drm/amd/display/dc/dcn21/dcn21_resource.c
@@ -296,7 +296,7 @@ struct _vcs_dpi_soc_bounding_box_st dcn2_1_soc = {
 	.num_banks = 8,
 	.num_chans = 4,
 	.vmm_page_size_bytes = 4096,
-	.dram_clock_change_latency_us = 23.84,
+	.dram_clock_change_latency_us = 11.72,
 	.return_bus_width_bytes = 64,
 	.dispclk_dppclk_vco_speed_mhz = 3600,
 	.xfc_bus_transport_time_us = 4,
-- 
2.25.1



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