Commit 12d0e503 authored by Derek Lai's avatar Derek Lai Committed by Alex Deucher
Browse files

drm/amd/display: Read max down spread 



[Why]
When launch D10.2, driver will write DPCD 0x107 with 0x00

[How]
Read MAX_DOWNSPREAD (0x0003h) then keep in current
link settings

Signed-off-by: default avatarDerek Lai <Derek.Lai@amd.com>
Reviewed-by: default avatarTony Cheng <Tony.Cheng@amd.com>
Acked-by: default avatarLeo Li <sunpeng.li@amd.com>
Signed-off-by: default avatarAlex Deucher <alexander.deucher@amd.com>
parent 288af96d

drivers/gpu/drm/amd/display/dc/core/dc_link.c

+7 −0
Original line number Diff line number Diff line
@@ -532,6 +532,7 @@ static void read_edp_current_link_settings_on_detect(struct dc_link *link) 
	uint32_t read_dpcd_retry_cnt = 10;

	enum dc_status status = DC_ERROR_UNEXPECTED;

	int i;

	union max_down_spread max_down_spread = { {0} };



	// Read DPCD 00101h to find out the number of lanes currently set

	for (i = 0; i < read_dpcd_retry_cnt; i++) {
@@ -576,6 +577,12 @@ static void read_edp_current_link_settings_on_detect(struct dc_link *link) 
		link->cur_link_settings.link_rate = link_bw_set;

		link->cur_link_settings.use_link_rate_set = false;

	}

	// Read DPCD 00003h to find the max down spread.

	core_link_read_dpcd(link, DP_MAX_DOWNSPREAD,

			&max_down_spread.raw, sizeof(max_down_spread));

	link->cur_link_settings.link_spread =

		max_down_spread.bits.MAX_DOWN_SPREAD ?

		LINK_SPREAD_05_DOWNSPREAD_30KHZ : LINK_SPREAD_DISABLED;

}



static bool detect_dp(

CRA Git | Maintained and supported by SUSTech CRA and CCSE