drm/amd/display: Update dram_clock_change_latency for DCN2.1

[WHY]
dram clock change latencies get updated using ddr4 latency table, but
does 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: Sung Lee <sung.lee@amd.com>
Reviewed-by: Tony Cheng <Tony.Cheng@amd.com>
Acked-by: Aurabindo Pillai <aurabindo.pillai@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

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 1c88d2e..b000b43 100644 (file)
--- 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,