From: Josip Pavic <Josip.Pavic@xxxxxxx>
[Why]
eDP v1.4 allows panels to report link rates other than RBR/HBR/HBR2, that
may be more optimal for the panel's timing. Power can be saved by using
a link rate closer to the required bandwidth of the panel's timing.
[How]
Scan the table of reported link rates from the panel, and select the
minimum link rate that satisfies the bandwidth requirements of the panel's
timing. Include a flag to make the feature optional.
Signed-off-by: Josip Pavic <Josip.Pavic@xxxxxxx>
Reviewed-by: Harry Wentland <Harry.Wentland@xxxxxxx>
Acked-by: Anthony Koo <Anthony.Koo@xxxxxxx>
Acked-by: Leo Li <sunpeng.li@xxxxxxx>
---
drivers/gpu/drm/amd/display/dc/core/dc_link_dp.c | 195 ++++++++++++++++-------
drivers/gpu/drm/amd/display/dc/dc.h | 6 +-
drivers/gpu/drm/amd/display/dc/dc_dp_types.h | 2 +
3 files changed, 140 insertions(+), 63 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 09d3012..8ad79df 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
@@ -93,12 +93,10 @@ static void dpcd_set_link_settings(
struct dc_link *link,
const struct link_training_settings *lt_settings)
{
- uint8_t rate = (uint8_t)
- (lt_settings->link_settings.link_rate);
+ uint8_t rate;
union down_spread_ctrl downspread = { {0} };
union lane_count_set lane_count_set = { {0} };
- uint8_t link_set_buffer[2];
downspread.raw = (uint8_t)
(lt_settings->link_settings.link_spread);
@@ -111,29 +109,42 @@ static void dpcd_set_link_settings(
lane_count_set.bits.POST_LT_ADJ_REQ_GRANTED =
link->dpcd_caps.max_ln_count.bits.POST_LT_ADJ_REQ_SUPPORTED;
- link_set_buffer[0] = rate;
- link_set_buffer[1] = lane_count_set.raw;
-
- core_link_write_dpcd(link, DP_LINK_BW_SET,
- link_set_buffer, 2);
core_link_write_dpcd(link, DP_DOWNSPREAD_CTRL,
&downspread.raw, sizeof(downspread));
+ core_link_write_dpcd(link, DP_LANE_COUNT_SET,
+ &lane_count_set.raw, 1);
+
if (link->dpcd_caps.dpcd_rev.raw >= DPCD_REV_14 &&
- (link->dpcd_caps.link_rate_set >= 1 &&
- link->dpcd_caps.link_rate_set <= 8)) {
+ lt_settings->link_settings.use_link_rate_set == true) {
+ rate = 0;
+ core_link_write_dpcd(link, DP_LINK_BW_SET, &rate, 1);
core_link_write_dpcd(link, DP_LINK_RATE_SET,
- &link->dpcd_caps.link_rate_set, 1);
+ <_settings->link_settings.link_rate_set, 1);
+ } else {
+ rate = (uint8_t) (lt_settings->link_settings.link_rate);
+ core_link_write_dpcd(link, DP_LINK_BW_SET, &rate, 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,
- lt_settings->link_settings.link_rate,
- DP_LANE_COUNT_SET,
- lt_settings->link_settings.lane_count,
- DP_DOWNSPREAD_CTRL,
- lt_settings->link_settings.link_spread);
+ if (rate) {
+ DC_LOG_HW_LINK_TRAINING("%s\n %x rate = %x\n %x lane = %x\n %x spread = %x\n",
+ __func__,
+ DP_LINK_BW_SET,
+ lt_settings->link_settings.link_rate,
+ DP_LANE_COUNT_SET,
+ lt_settings->link_settings.lane_count,
+ DP_DOWNSPREAD_CTRL,
+ lt_settings->link_settings.link_spread);
+ } else {
+ DC_LOG_HW_LINK_TRAINING("%s\n %x rate set = %x\n %x lane = %x\n %x spread = %x\n",
+ __func__,
+ DP_LINK_RATE_SET,
+ lt_settings->link_settings.link_rate_set,
+ DP_LANE_COUNT_SET,
+ lt_settings->link_settings.lane_count,
+ DP_DOWNSPREAD_CTRL,
+ lt_settings->link_settings.link_spread);
+ }
}
@@ -952,6 +963,8 @@ enum link_training_result dc_link_dp_perform_link_training(
lt_settings.link_settings.link_rate = link_setting->link_rate;
lt_settings.link_settings.lane_count = link_setting->lane_count;
+ lt_settings.link_settings.use_link_rate_set = link_setting->use_link_rate_set;
+ lt_settings.link_settings.link_rate_set = link_setting->link_rate_set;
/*@todo[vdevulap] move SS to LS, should not be handled by displaypath*/
@@ -1075,7 +1088,7 @@ static struct dc_link_settings get_max_link_cap(struct dc_link *link)
{
/* Set Default link settings */
struct dc_link_settings max_link_cap = {LANE_COUNT_FOUR, LINK_RATE_HIGH,
- LINK_SPREAD_05_DOWNSPREAD_30KHZ};
+ LINK_SPREAD_05_DOWNSPREAD_30KHZ, false, 0};
/* Higher link settings based on feature supported */
if (link->link_enc->features.flags.bits.IS_HBR2_CAPABLE)
@@ -1629,47 +1642,65 @@ bool dp_validate_mode_timing(
return false;
}
-void decide_link_settings(struct dc_stream_state *stream,
- struct dc_link_settings *link_setting)
+static bool decide_dp_link_settings(struct dc_link *link, struct dc_link_settings *link_setting, uint32_t req_bw)
{
-
struct dc_link_settings initial_link_setting = {
- LANE_COUNT_ONE, LINK_RATE_LOW, LINK_SPREAD_DISABLED};
+ LANE_COUNT_ONE, LINK_RATE_LOW, LINK_SPREAD_DISABLED, false, 0};
struct dc_link_settings current_link_setting =
initial_link_setting;
- struct dc_link *link;
- uint32_t req_bw;
uint32_t link_bw;
- req_bw = bandwidth_in_kbps_from_timing(&stream->timing);
-
- link = stream->link;
-
- /* if preferred is specified through AMDDP, use it, if it's enough
- * to drive the mode
+ /* search for the minimum link setting that:
+ * 1. is supported according to the link training result
+ * 2. could support the b/w requested by the timing
*/
- if (link->preferred_link_setting.lane_count !=
- LANE_COUNT_UNKNOWN &&
- link->preferred_link_setting.link_rate !=
- LINK_RATE_UNKNOWN) {
- *link_setting = link->preferred_link_setting;
- return;
- }
+ while (current_link_setting.link_rate <=
+ link->verified_link_cap.link_rate) {
+ link_bw = bandwidth_in_kbps_from_link_settings(
+ ¤t_link_setting);
+ if (req_bw <= link_bw) {
+ *link_setting = current_link_setting;
+ return true;
+ }
- /* MST doesn't perform link training for now
- * TODO: add MST specific link training routine
- */
- if (stream->signal == SIGNAL_TYPE_DISPLAY_PORT_MST) {
- *link_setting = link->verified_link_cap;
- return;
+ if (current_link_setting.lane_count <
+ link->verified_link_cap.lane_count) {
+ current_link_setting.lane_count =
+ increase_lane_count(
+ current_link_setting.lane_count);
+ } else {
+ current_link_setting.link_rate =
+ increase_link_rate(
+ current_link_setting.link_rate);
+ current_link_setting.lane_count =
+ initial_link_setting.lane_count;
+ }
}
- /* EDP use the link cap setting */
- if (link->connector_signal == SIGNAL_TYPE_EDP) {
+ return false;
+}
+
+static bool decide_edp_link_settings(struct dc_link *link, struct dc_link_settings *link_setting, uint32_t req_bw)
+{
+ struct dc_link_settings initial_link_setting;
+ struct dc_link_settings current_link_setting;
+ uint32_t link_bw;
+
+ if (link->dpcd_caps.dpcd_rev.raw < DPCD_REV_14 ||
+ link->dpcd_caps.edp_supported_link_rates_count == 0 ||
+ link->dc->config.optimize_edp_link_rate == false) {
*link_setting = link->verified_link_cap;
- return;
+ return true;
}
+ memset(&initial_link_setting, 0, sizeof(initial_link_setting));
+ initial_link_setting.lane_count = LANE_COUNT_ONE;
+ initial_link_setting.link_rate = link->dpcd_caps.edp_supported_link_rates[0];
+ initial_link_setting.link_spread = LINK_SPREAD_DISABLED;
+ initial_link_setting.use_link_rate_set = true;
+ initial_link_setting.link_rate_set = 0;
+ current_link_setting = initial_link_setting;
+
/* search for the minimum link setting that:
* 1. is supported according to the link training result
* 2. could support the b/w requested by the timing
@@ -1680,7 +1711,7 @@ void decide_link_settings(struct dc_stream_state *stream,
¤t_link_setting);
if (req_bw <= link_bw) {
*link_setting = current_link_setting;
- return;
+ return true;
}
if (current_link_setting.lane_count <
@@ -1689,13 +1720,53 @@ void decide_link_settings(struct dc_stream_state *stream,
increase_lane_count(
current_link_setting.lane_count);
} else {
- current_link_setting.link_rate =
- increase_link_rate(
- current_link_setting.link_rate);
- current_link_setting.lane_count =
- initial_link_setting.lane_count;
+ if (current_link_setting.link_rate_set < link->dpcd_caps.edp_supported_link_rates_count) {
+ current_link_setting.link_rate_set++;
+ current_link_setting.link_rate =
+ link->dpcd_caps.edp_supported_link_rates[current_link_setting.link_rate_set];
+ current_link_setting.lane_count =
+ initial_link_setting.lane_count;
+ } else
+ break;
}
}
+ return false;
+}
+
+void decide_link_settings(struct dc_stream_state *stream,
+ struct dc_link_settings *link_setting)
+{
+ struct dc_link *link;
+ uint32_t req_bw;
+
+ req_bw = bandwidth_in_kbps_from_timing(&stream->timing);
+
+ link = stream->link;
+
+ /* if preferred is specified through AMDDP, use it, if it's enough
+ * to drive the mode
+ */
+ if (link->preferred_link_setting.lane_count !=
+ LANE_COUNT_UNKNOWN &&
+ link->preferred_link_setting.link_rate !=
+ LINK_RATE_UNKNOWN) {
+ *link_setting = link->preferred_link_setting;
+ return;
+ }
+
+ /* MST doesn't perform link training for now
+ * TODO: add MST specific link training routine
+ */
+ if (stream->signal == SIGNAL_TYPE_DISPLAY_PORT_MST) {
+ *link_setting = link->verified_link_cap;
+ return;
+ }
+
+ if (link->connector_signal == SIGNAL_TYPE_EDP) {
+ if (decide_edp_link_settings(link, link_setting, req_bw))
+ return;
+ } else if (decide_dp_link_settings(link, link_setting, req_bw))
+ return;
BREAK_TO_DEBUGGER();
ASSERT(link->verified_link_cap.lane_count != LANE_COUNT_UNKNOWN);
@@ -2536,31 +2607,31 @@ enum dc_link_rate linkRateInKHzToLinkRateMultiplier(uint32_t link_rate_in_khz)
void detect_edp_sink_caps(struct dc_link *link)
{
- uint8_t supported_link_rates[16] = {0};
+ uint8_t supported_link_rates[16];
uint32_t entry;
uint32_t link_rate_in_khz;
enum dc_link_rate link_rate = LINK_RATE_UNKNOWN;
retrieve_link_cap(link);
+ link->dpcd_caps.edp_supported_link_rates_count = 0;
+ memset(supported_link_rates, 0, sizeof(supported_link_rates));
- if (link->dpcd_caps.dpcd_rev.raw >= DPCD_REV_14) {
+ if (link->dpcd_caps.dpcd_rev.raw >= DPCD_REV_14 &&
+ link->dc->config.optimize_edp_link_rate) {
// 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.
+ // value X 200 kHz. Need multiplier 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;
- link->dpcd_caps.link_rate_set = entry;
- }
+ link->dpcd_caps.edp_supported_link_rates[link->dpcd_caps.edp_supported_link_rates_count] = link_rate;
+ link->dpcd_caps.edp_supported_link_rates_count++;
}
}
}
diff --git a/drivers/gpu/drm/amd/display/dc/dc.h b/drivers/gpu/drm/amd/display/dc/dc.h
index a4d3da8..e98e19c 100644
--- a/drivers/gpu/drm/amd/display/dc/dc.h
+++ b/drivers/gpu/drm/amd/display/dc/dc.h
@@ -164,6 +164,7 @@ struct dc_config {
bool gpu_vm_support;
bool disable_disp_pll_sharing;
bool fbc_support;
+ bool optimize_edp_link_rate;
};
enum visual_confirm {
@@ -648,6 +649,10 @@ struct dpcd_caps {
union max_lane_count max_ln_count;
union max_down_spread max_down_spread;
+ /* valid only for eDP v1.4 or higher*/
+ uint8_t edp_supported_link_rates_count;
+ enum dc_link_rate edp_supported_link_rates[8];
+
/* dongle type (DP converter, CV smart dongle) */
enum display_dongle_type dongle_type;
/* Dongle's downstream count. */
@@ -665,7 +670,6 @@ 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 d4eab33..ec403cd 100644
--- a/drivers/gpu/drm/amd/display/dc/dc_dp_types.h
+++ b/drivers/gpu/drm/amd/display/dc/dc_dp_types.h
@@ -94,6 +94,8 @@ struct dc_link_settings {
enum dc_lane_count lane_count;
enum dc_link_rate link_rate;
enum dc_link_spread link_spread;
+ bool use_link_rate_set;
+ uint8_t link_rate_set;
};
struct dc_lane_settings {
--
2.7.4
_______________________________________________
amd-gfx mailing list
amd-gfx@xxxxxxxxxxxxxxxxxxxxx
https://lists.freedesktop.org/mailman/listinfo/amd-gfx
