From: Derek Lai <Derek.Lai@xxxxxxx>
[Why]
If eDP ver >= 1.4,
the Source device must use LINK_RATE_SET.
[How]
Get LINK_RATE_SET by reading DPCD 10h-1fh,
then write DPCD 00115h before link training.
Signed-off-by: Derek Lai <Derek.Lai@xxxxxxx>
Reviewed-by: Tony Cheng <Tony.Cheng@xxxxxxx>
Acked-by: Leo Li <sunpeng.li@xxxxxxx>
---
drivers/gpu/drm/amd/display/dc/core/dc_link_dp.c | 105 ++++++++++++++++++++++-
drivers/gpu/drm/amd/display/dc/dc.h | 1 +
drivers/gpu/drm/amd/display/dc/dc_dp_types.h | 13 +--
3 files changed, 111 insertions(+), 8 deletions(-)
diff --git a/drivers/gpu/drm/amd/display/dc/core/dc_link_dp.c b/drivers/gpu/drm/amd/display/dc/core/dc_link_dp.c
index cf93627..431805c 100644
--- a/drivers/gpu/drm/amd/display/dc/core/dc_link_dp.c
+++ b/drivers/gpu/drm/amd/display/dc/core/dc_link_dp.c
@@ -117,6 +117,13 @@ static void dpcd_set_link_settings(
core_link_write_dpcd(link, DP_DOWNSPREAD_CTRL,
&downspread.raw, sizeof(downspread));
+ if (link->dpcd_caps.dpcd_rev.raw >= DPCD_REV_14 &&
+ (link->dpcd_caps.link_rate_set >= 1 &&
+ link->dpcd_caps.link_rate_set <= 8)) {
+ core_link_write_dpcd(link, DP_LINK_RATE_SET,
+ &link->dpcd_caps.link_rate_set, 1);
+ }
+
DC_LOG_HW_LINK_TRAINING("%s\n %x rate = %x\n %x lane = %x\n %x spread = %x\n",
__func__,
DP_LINK_BW_SET,
@@ -2489,13 +2496,105 @@ bool detect_dp_sink_caps(struct dc_link *link)
/* TODO save sink caps in link->sink */
}
+enum dc_link_rate linkRateInKHzToLinkRateMultiplier(uint32_t link_rate_in_khz)
+{
+ enum dc_link_rate link_rate;
+ // LinkRate is normally stored as a multiplier of 0.27 Gbps per lane. Do the translation.
+ switch (link_rate_in_khz) {
+ case 1620000:
+ link_rate = LINK_RATE_LOW; // Rate_1 (RBR) - 1.62 Gbps/Lane
+ break;
+ case 2160000:
+ link_rate = LINK_RATE_RATE_2; // Rate_2 - 2.16 Gbps/Lane
+ break;
+ case 2430000:
+ link_rate = LINK_RATE_RATE_3; // Rate_3 - 2.43 Gbps/Lane
+ break;
+ case 2700000:
+ link_rate = LINK_RATE_HIGH; // Rate_4 (HBR) - 2.70 Gbps/Lane
+ break;
+ case 3240000:
+ link_rate = LINK_RATE_RBR2; // Rate_5 (RBR2) - 3.24 Gbps/Lane
+ break;
+ case 4320000:
+ link_rate = LINK_RATE_RATE_6; // Rate_6 - 4.32 Gbps/Lane
+ break;
+ case 5400000:
+ link_rate = LINK_RATE_HIGH2; // Rate_7 (HBR2) - 5.40 Gbps/Lane
+ break;
+ case 8100000:
+ link_rate = LINK_RATE_HIGH3; // Rate_8 (HBR3) - 8.10 Gbps/Lane
+ break;
+ default:
+ link_rate = LINK_RATE_UNKNOWN;
+ break;
+ }
+ return link_rate;
+}
+
void detect_edp_sink_caps(struct dc_link *link)
{
- retrieve_link_cap(link);
+ uint8_t supported_link_rates[16] = {0};
+ uint32_t entry;
+ uint32_t link_rate_in_khz;
+ enum dc_link_rate link_rate = LINK_RATE_UNKNOWN;
+ uint8_t link_rate_set = 0;
- if (link->reported_link_cap.link_rate == LINK_RATE_UNKNOWN)
- link->reported_link_cap.link_rate = LINK_RATE_HIGH2;
+ retrieve_link_cap(link);
+ if (link->dpcd_caps.dpcd_rev.raw >= DPCD_REV_14) {
+ // Read DPCD 00010h - 0001Fh 16 bytes at one shot
+ core_link_read_dpcd(link, DP_SUPPORTED_LINK_RATES,
+ supported_link_rates, sizeof(supported_link_rates));
+
+ link->dpcd_caps.link_rate_set = 0;
+ for (entry = 0; entry < 16; entry += 2) {
+ // DPCD register reports per-lane link rate = 16-bit link rate capability
+ // value X 200 kHz. Need multipler to find link rate in kHz.
+ link_rate_in_khz = (supported_link_rates[entry+1] * 0x100 +
+ supported_link_rates[entry]) * 200;
+
+ if (link_rate_in_khz != 0) {
+ link_rate = linkRateInKHzToLinkRateMultiplier(link_rate_in_khz);
+ if (link->reported_link_cap.link_rate < link_rate) {
+ link->reported_link_cap.link_rate = link_rate;
+
+ switch (link_rate) {
+ case LINK_RATE_LOW:
+ link_rate_set = 1;
+ break;
+ case LINK_RATE_RATE_2:
+ link_rate_set = 2;
+ break;
+ case LINK_RATE_RATE_3:
+ link_rate_set = 3;
+ break;
+ case LINK_RATE_HIGH:
+ link_rate_set = 4;
+ break;
+ case LINK_RATE_RBR2:
+ link_rate_set = 5;
+ break;
+ case LINK_RATE_RATE_6:
+ link_rate_set = 6;
+ break;
+ case LINK_RATE_HIGH2:
+ link_rate_set = 7;
+ break;
+ case LINK_RATE_HIGH3:
+ link_rate_set = 8;
+ break;
+ default:
+ link_rate_set = 0;
+ break;
+ }
+
+ if (link->dpcd_caps.link_rate_set < link_rate_set)
+ link->dpcd_caps.link_rate_set = link_rate_set;
+ }
+ }
+ }
+ }
link->verified_link_cap = link->reported_link_cap;
}
diff --git a/drivers/gpu/drm/amd/display/dc/dc.h b/drivers/gpu/drm/amd/display/dc/dc.h
index f80f52e..1c46249 100644
--- a/drivers/gpu/drm/amd/display/dc/dc.h
+++ b/drivers/gpu/drm/amd/display/dc/dc.h
@@ -659,6 +659,7 @@ struct dpcd_caps {
int8_t branch_dev_name[6];
int8_t branch_hw_revision;
int8_t branch_fw_revision[2];
+ uint8_t link_rate_set;
bool allow_invalid_MSA_timing_param;
bool panel_mode_edp;
diff --git a/drivers/gpu/drm/amd/display/dc/dc_dp_types.h b/drivers/gpu/drm/amd/display/dc/dc_dp_types.h
index da93ab4..d4eab33 100644
--- a/drivers/gpu/drm/amd/display/dc/dc_dp_types.h
+++ b/drivers/gpu/drm/amd/display/dc/dc_dp_types.h
@@ -46,11 +46,14 @@ enum dc_lane_count {
*/
enum dc_link_rate {
LINK_RATE_UNKNOWN = 0,
- LINK_RATE_LOW = 0x06,
- LINK_RATE_HIGH = 0x0A,
- LINK_RATE_RBR2 = 0x0C,
- LINK_RATE_HIGH2 = 0x14,
- LINK_RATE_HIGH3 = 0x1E
+ LINK_RATE_LOW = 0x06, // Rate_1 (RBR) - 1.62 Gbps/Lane
+ LINK_RATE_RATE_2 = 0x08, // Rate_2 - 2.16 Gbps/Lane
+ LINK_RATE_RATE_3 = 0x09, // Rate_3 - 2.43 Gbps/Lane
+ LINK_RATE_HIGH = 0x0A, // Rate_4 (HBR) - 2.70 Gbps/Lane
+ LINK_RATE_RBR2 = 0x0C, // Rate_5 (RBR2)- 3.24 Gbps/Lane
+ LINK_RATE_RATE_6 = 0x10, // Rate_6 - 4.32 Gbps/Lane
+ LINK_RATE_HIGH2 = 0x14, // Rate_7 (HBR2)- 5.40 Gbps/Lane
+ LINK_RATE_HIGH3 = 0x1E // Rate_8 (HBR3)- 8.10 Gbps/Lane
};
enum dc_link_spread {
--
2.7.4
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