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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: Derek Lai <Derek.Lai@amd.com>
Reviewed-by: Tony Cheng <Tony.Cheng@amd.com>
Acked-by: Leo Li <sunpeng.li@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
This commit is contained in:
Derek Lai 2019-06-18 14:55:57 +08:00 committed by Alex Deucher
parent 288af96df1
commit 12d0e503dd
1 changed files with 7 additions and 0 deletions
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7
drivers/gpu/drm/amd/display/dc/core/dc_link.c
View File

@ -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(