[Intel-gfx] [PATCH v14 13/14] drm/i915/dp: Enable Upfront link training for typeC DP support on HSW/BDW/SKL/BXT (DDI platforms)
Jani Nikula
jani.nikula at linux.intel.com
Fri Sep 9 07:31:31 UTC 2016
On Thu, 08 Sep 2016, Manasi Navare <manasi.d.navare at intel.com> wrote:
> From: Durgadoss R <durgadoss.r at intel.com>
>
> To support USB type C alternate DP mode, the display driver needs to
> know the number of lanes required by the DP panel as well as number
> of lanes that can be supported by the type-C cable. Sometimes, the
> type-C cable may limit the bandwidth even if Panel can support
> more lanes. To address these scenarios, the display driver will
> start link training with max lanes, and if that fails, the driver
> falls back to x2 lanes; and repeats this procedure for all
> bandwidth/lane configurations.
Please do not combine non-functional code movement with real
changes. They must be separated.
BR,
Jani.
>
> * Since link training is done before modeset only the port
> (and not pipe/planes) and its associated PLLs are enabled.
> * On DP hotplug: Directly start link training on the DP encoder.
> * On Connected boot scenarios: When booted with an LFP and a DP,
> sometimes BIOS brings up DP. In these cases, we disable the
> crtc and then do upfront link training; and bring it back up.
> * All local changes made for upfront link training are reset
> to their previous values once it is done; so that the
> subsequent modeset is not aware of these changes.
>
> Changes since v13:
> * Fix some indentation issues (Mika Kahola)
> Changes since v12:
> * Fix Rebase issues (Mika Kahola)
> Changes since v11:
> * Change the fallback link rate logic (Manasi)
> Changes since v10:
> * Use the ddi link train function that loops through all the link rates
> and lane counts starting from the highest supported (Manasi)
> * For upfront link training, set the upfront flag so that the link can
> be disabled after caching upfront values (Manasi)
> Changes since v9:
> * Change the macros to use dev_priv in place of dev (David Weinehall)
> Changes since v8:
> * Reset upfront lane count and link rate values on HPD
> for DP connector physical disconnect (Manasi)
> Changes since v7:
> * Move the upfront link training to intel_dp_mode_valid()
> to avoid a race condition with DP MST sideband comms. (Ville)
> Changes since v6:
> * Fix some initialization bugs on link_rate (Jim Bride)
> * Use link_rate (and not link_bw) for upfront (Ville)
> * Make intel_dp_upfront*() as a vfunc (Ander)
> * The train_set_valid variable in intel_dp was removed due to
> issues in fast link training. So, to indicate the link train
> status, move the channel_eq inside intel_dp.
> Changes since v5:
> * Moved retry logic in upfront to intel_dp.c so that it
> can be used for all platforms.
> Changes since v4:
> * Removed usage of crtc_state in upfront link training;
> Hence no need to find free crtc to do upfront now.
> * Re-enable crtc if it was disabled for upfront.
> * Use separate variables to track max lane count
> and link rate found by upfront, without modifying
> the original DPCD read from panel.
> Changes since v3:
> * Fixed a return value on BXT check
> * Reworked on top of bxt_ddi_pll_select split from Ander
> * Renamed from ddi_upfront to bxt_upfront since the
> upfront logic includes BXT specific functions for now.
> Changes since v2:
> * Rebased on top of latest dpll_mgr.c code and
> latest HPD related clean ups.
> * Corrected return values from upfront (Ander)
> * Corrected atomic locking for upfront in intel_dp.c (Ville)
> Changes since v1:
> * all pll related functions inside ddi.c
>
> Signed-off-by: Durgadoss R <durgadoss.r at intel.com>
> Signed-off-by: Jim Bride <jim.bride at linux.intel.com>
> Signed-off-by: Manasi Navare <manasi.d.navare at intel.com>
> ---
> drivers/gpu/drm/i915/intel_ddi.c | 21 +-
> drivers/gpu/drm/i915/intel_dp.c | 377 +++++++++++++++++++-------
> drivers/gpu/drm/i915/intel_dp_link_training.c | 1 -
> drivers/gpu/drm/i915/intel_drv.h | 14 +-
> 4 files changed, 311 insertions(+), 102 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/intel_ddi.c b/drivers/gpu/drm/i915/intel_ddi.c
> index 1278daa..797c3bb 100644
> --- a/drivers/gpu/drm/i915/intel_ddi.c
> +++ b/drivers/gpu/drm/i915/intel_ddi.c
> @@ -1673,7 +1673,8 @@ static void intel_ddi_pre_enable_dp(struct intel_encoder *encoder,
> pll->config.crtc_mask = 0;
>
> /* If Link Training fails, send a uevent to generate a hotplug */
> - if (!(intel_ddi_link_train(intel_dp, link_rate, lane_count, link_mst)))
> + if (!(intel_ddi_link_train(intel_dp, link_rate, lane_count, link_mst,
> + false)))
> drm_kms_helper_hotplug_event(encoder->base.dev);
> pll->config = tmp_pll_config;
> }
> @@ -2461,7 +2462,7 @@ intel_ddi_get_link_dpll(struct intel_dp *intel_dp, int clock)
>
> bool
> intel_ddi_link_train(struct intel_dp *intel_dp, int max_link_rate,
> - uint8_t max_lane_count, bool link_mst)
> + uint8_t max_lane_count, bool link_mst, bool is_upfront)
> {
> struct intel_connector *connector = intel_dp->attached_connector;
> struct intel_encoder *encoder = connector->encoder;
> @@ -2507,6 +2508,7 @@ intel_ddi_link_train(struct intel_dp *intel_dp, int max_link_rate,
> pll->funcs.disable(dev_priv, pll);
> pll->config = tmp_pll_config;
> }
> +
> if (ret) {
> DRM_DEBUG_KMS("Link Training successful at link rate: "
> "%d lane:%d\n", link_rate, lane_count);
> @@ -2515,6 +2517,21 @@ intel_ddi_link_train(struct intel_dp *intel_dp, int max_link_rate,
> }
> intel_dp_stop_link_train(intel_dp);
>
> + if (is_upfront) {
> + DRM_DEBUG_KMS("Upfront link train %s: link_clock:%d lanes:%d\n",
> + ret ? "Passed" : "Failed",
> + link_rate, lane_count);
> + /* Disable port followed by PLL for next retry/clean up */
> + intel_ddi_post_disable(encoder, NULL, NULL);
> + pll->funcs.disable(dev_priv, pll);
> + pll->config = tmp_pll_config;
> + if (ret) {
> + /* Save the upfront values */
> + intel_dp->max_lanes_upfront = lane_count;
> + intel_dp->max_link_rate_upfront = link_rate;
> + }
> + }
> +
> if (!lane_count)
> DRM_ERROR("Link Training Failed\n");
>
> diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
> index 853e97d..3d76968 100644
> --- a/drivers/gpu/drm/i915/intel_dp.c
> +++ b/drivers/gpu/drm/i915/intel_dp.c
> @@ -153,12 +153,21 @@ intel_dp_max_link_bw(struct intel_dp *intel_dp)
> static u8 intel_dp_max_lane_count(struct intel_dp *intel_dp)
> {
> struct intel_digital_port *intel_dig_port = dp_to_dig_port(intel_dp);
> - u8 source_max, sink_max;
> + u8 temp, source_max, sink_max;
>
> source_max = intel_dig_port->max_lanes;
> sink_max = drm_dp_max_lane_count(intel_dp->dpcd);
>
> - return min(source_max, sink_max);
> + temp = min(source_max, sink_max);
> +
> + /*
> + * Limit max lanes w.r.t to the max value found
> + * using Upfront link training also.
> + */
> + if (intel_dp->max_lanes_upfront)
> + return min(temp, intel_dp->max_lanes_upfront);
> + else
> + return temp;
> }
>
> /*
> @@ -190,6 +199,230 @@ intel_dp_max_data_rate(int max_link_clock, int max_lanes)
> return (max_link_clock * max_lanes * 8) / 10;
> }
>
> +static int intel_dp_upfront_crtc_disable(struct intel_crtc *crtc,
> + struct drm_modeset_acquire_ctx *ctx,
> + bool enable)
> +{
> + int ret;
> + struct drm_atomic_state *state;
> + struct intel_crtc_state *crtc_state;
> + struct drm_device *dev = crtc->base.dev;
> + enum pipe pipe = crtc->pipe;
> +
> + state = drm_atomic_state_alloc(dev);
> + if (!state)
> + return -ENOMEM;
> +
> + state->acquire_ctx = ctx;
> +
> + crtc_state = intel_atomic_get_crtc_state(state, crtc);
> + if (IS_ERR(crtc_state)) {
> + ret = PTR_ERR(crtc_state);
> + drm_atomic_state_free(state);
> + return ret;
> + }
> +
> + DRM_DEBUG_KMS("%sabling crtc %c %s upfront link train\n",
> + enable ? "En" : "Dis",
> + pipe_name(pipe),
> + enable ? "after" : "before");
> +
> + crtc_state->base.active = enable;
> + ret = drm_atomic_commit(state);
> + if (ret)
> + drm_atomic_state_free(state);
> +
> + return ret;
> +}
> +
> +static int
> +intel_dp_sink_rates(struct intel_dp *intel_dp, const int **sink_rates)
> +{
> + if (intel_dp->num_sink_rates) {
> + *sink_rates = intel_dp->sink_rates;
> + return intel_dp->num_sink_rates;
> + }
> +
> + *sink_rates = default_rates;
> +
> + return (intel_dp_max_link_bw(intel_dp) >> 3) + 1;
> +}
> +
> +bool intel_dp_source_supports_hbr2(struct intel_dp *intel_dp)
> +{
> + struct intel_digital_port *dig_port = dp_to_dig_port(intel_dp);
> + struct drm_i915_private *dev_priv = to_i915(dig_port->base.base.dev);
> +
> + /* WaDisableHBR2:skl */
> + if (IS_SKL_REVID(dev_priv, 0, SKL_REVID_B0))
> + return false;
> +
> + if ((IS_HASWELL(dev_priv) && !IS_HSW_ULX(dev_priv)) ||
> + IS_BROADWELL(dev_priv) || (INTEL_GEN(dev_priv) >= 9))
> + return true;
> + else
> + return false;
> +}
> +
> +static int
> +intel_dp_source_rates(struct intel_dp *intel_dp, const int **source_rates)
> +{
> + struct intel_digital_port *dig_port = dp_to_dig_port(intel_dp);
> + struct drm_i915_private *dev_priv = to_i915(dig_port->base.base.dev);
> + int size;
> +
> + if (IS_BROXTON(dev_priv)) {
> + *source_rates = bxt_rates;
> + size = ARRAY_SIZE(bxt_rates);
> + } else if (IS_SKYLAKE(dev_priv) || IS_KABYLAKE(dev_priv)) {
> + *source_rates = skl_rates;
> + size = ARRAY_SIZE(skl_rates);
> + } else {
> + *source_rates = default_rates;
> + size = ARRAY_SIZE(default_rates);
> + }
> +
> + /* This depends on the fact that 5.4 is last value in the array */
> + if (!intel_dp_source_supports_hbr2(intel_dp))
> + size--;
> +
> + return size;
> +}
> +
> +static int intersect_rates(const int *source_rates, int source_len,
> + const int *sink_rates, int sink_len,
> + int *common_rates)
> +{
> + int i = 0, j = 0, k = 0;
> +
> + while (i < source_len && j < sink_len) {
> + if (source_rates[i] == sink_rates[j]) {
> + if (WARN_ON(k >= DP_MAX_SUPPORTED_RATES))
> + return k;
> + common_rates[k] = source_rates[i];
> + ++k;
> + ++i;
> + ++j;
> + } else if (source_rates[i] < sink_rates[j]) {
> + ++i;
> + } else {
> + ++j;
> + }
> + }
> + return k;
> +}
> +
> +static int intel_dp_common_rates(struct intel_dp *intel_dp,
> + int *common_rates)
> +{
> + const int *source_rates, *sink_rates;
> + int source_len, sink_len;
> +
> + sink_len = intel_dp_sink_rates(intel_dp, &sink_rates);
> +
> + /* Cap sink rates w.r.t upfront values */
> + if (intel_dp->max_link_rate_upfront) {
> + int len = sink_len - 1;
> +
> + while (len > 0 && sink_rates[len] >
> + intel_dp->max_link_rate_upfront)
> + len--;
> + sink_len = len + 1;
> + }
> +
> + source_len = intel_dp_source_rates(intel_dp, &source_rates);
> +
> + return intersect_rates(source_rates, source_len,
> + sink_rates, sink_len,
> + common_rates);
> +}
> +
> +static bool intel_dp_upfront_link_train(struct intel_dp *intel_dp)
> +{
> + struct intel_digital_port *intel_dig_port = dp_to_dig_port(intel_dp);
> + struct intel_encoder *intel_encoder = &intel_dig_port->base;
> + struct drm_device *dev = intel_encoder->base.dev;
> + struct drm_i915_private *dev_priv = to_i915(dev);
> + struct drm_mode_config *config = &dev->mode_config;
> + struct drm_modeset_acquire_ctx ctx;
> + struct intel_crtc *intel_crtc;
> + struct drm_crtc *crtc = NULL;
> + struct intel_shared_dpll *pll;
> + struct intel_shared_dpll_config tmp_pll_config;
> + bool disable_dpll = false;
> + int ret;
> + bool done = false, has_mst = false;
> + uint8_t max_lanes;
> + int common_rates[DP_MAX_SUPPORTED_RATES] = {};
> + int common_len;
> + enum intel_display_power_domain power_domain;
> +
> + power_domain = intel_display_port_power_domain(intel_encoder);
> + intel_display_power_get(dev_priv, power_domain);
> +
> + common_len = intel_dp_common_rates(intel_dp, common_rates);
> + max_lanes = intel_dp_max_lane_count(intel_dp);
> + if (WARN_ON(common_len <= 0))
> + return true;
> +
> + drm_modeset_acquire_init(&ctx, 0);
> +retry:
> + ret = drm_modeset_lock(&config->connection_mutex, &ctx);
> + if (ret)
> + goto exit_fail;
> +
> + if (intel_encoder->base.crtc) {
> + crtc = intel_encoder->base.crtc;
> +
> + ret = drm_modeset_lock(&crtc->mutex, &ctx);
> + if (ret)
> + goto exit_fail;
> +
> + ret = drm_modeset_lock(&crtc->primary->mutex, &ctx);
> + if (ret)
> + goto exit_fail;
> +
> + intel_crtc = to_intel_crtc(crtc);
> + pll = intel_crtc->config->shared_dpll;
> + disable_dpll = true;
> + has_mst = intel_crtc_has_type(intel_crtc->config,
> + INTEL_OUTPUT_DP_MST);
> + ret = intel_dp_upfront_crtc_disable(intel_crtc, &ctx, false);
> + if (ret)
> + goto exit_fail;
> + }
> +
> + mutex_lock(&dev_priv->dpll_lock);
> + if (disable_dpll) {
> + /* Clear the PLL config state */
> + tmp_pll_config = pll->config;
> + pll->config.crtc_mask = 0;
> + }
> +
> + done = intel_dp->upfront_link_train(intel_dp,
> + common_rates[common_len-1],
> + max_lanes,
> + has_mst,
> + true);
> + if (disable_dpll)
> + pll->config = tmp_pll_config;
> +
> + mutex_unlock(&dev_priv->dpll_lock);
> +
> + if (crtc)
> + ret = intel_dp_upfront_crtc_disable(intel_crtc, &ctx, true);
> +
> +exit_fail:
> + if (ret == -EDEADLK) {
> + drm_modeset_backoff(&ctx);
> + goto retry;
> + }
> + drm_modeset_drop_locks(&ctx);
> + drm_modeset_acquire_fini(&ctx);
> + intel_display_power_put(dev_priv, power_domain);
> + return done;
> +}
> +
> static enum drm_mode_status
> intel_dp_mode_valid(struct drm_connector *connector,
> struct drm_display_mode *mode)
> @@ -211,6 +444,19 @@ intel_dp_mode_valid(struct drm_connector *connector,
> target_clock = fixed_mode->clock;
> }
>
> + if (intel_dp->upfront_link_train && !intel_dp->upfront_done) {
> + bool do_upfront_link_train;
> + /* Do not do upfront link train, if it is a compliance
> + * request
> + */
> + do_upfront_link_train = !intel_dp->upfront_done &&
> + (intel_dp->compliance_test_type !=
> + DP_TEST_LINK_TRAINING);
> +
> + if (do_upfront_link_train)
> + intel_dp->upfront_done = intel_dp_upfront_link_train(intel_dp);
> + }
> +
> max_link_clock = intel_dp_max_link_rate(intel_dp);
> max_lanes = intel_dp_max_lane_count(intel_dp);
>
> @@ -1256,60 +1502,6 @@ intel_dp_aux_init(struct intel_dp *intel_dp, struct intel_connector *connector)
> intel_dp->aux.transfer = intel_dp_aux_transfer;
> }
>
> -static int
> -intel_dp_sink_rates(struct intel_dp *intel_dp, const int **sink_rates)
> -{
> - if (intel_dp->num_sink_rates) {
> - *sink_rates = intel_dp->sink_rates;
> - return intel_dp->num_sink_rates;
> - }
> -
> - *sink_rates = default_rates;
> -
> - return (intel_dp_max_link_bw(intel_dp) >> 3) + 1;
> -}
> -
> -bool intel_dp_source_supports_hbr2(struct intel_dp *intel_dp)
> -{
> - struct intel_digital_port *dig_port = dp_to_dig_port(intel_dp);
> - struct drm_device *dev = dig_port->base.base.dev;
> -
> - /* WaDisableHBR2:skl */
> - if (IS_SKL_REVID(dev, 0, SKL_REVID_B0))
> - return false;
> -
> - if ((IS_HASWELL(dev) && !IS_HSW_ULX(dev)) || IS_BROADWELL(dev) ||
> - (INTEL_INFO(dev)->gen >= 9))
> - return true;
> - else
> - return false;
> -}
> -
> -static int
> -intel_dp_source_rates(struct intel_dp *intel_dp, const int **source_rates)
> -{
> - struct intel_digital_port *dig_port = dp_to_dig_port(intel_dp);
> - struct drm_device *dev = dig_port->base.base.dev;
> - int size;
> -
> - if (IS_BROXTON(dev)) {
> - *source_rates = bxt_rates;
> - size = ARRAY_SIZE(bxt_rates);
> - } else if (IS_SKYLAKE(dev) || IS_KABYLAKE(dev)) {
> - *source_rates = skl_rates;
> - size = ARRAY_SIZE(skl_rates);
> - } else {
> - *source_rates = default_rates;
> - size = ARRAY_SIZE(default_rates);
> - }
> -
> - /* This depends on the fact that 5.4 is last value in the array */
> - if (!intel_dp_source_supports_hbr2(intel_dp))
> - size--;
> -
> - return size;
> -}
> -
> static void
> intel_dp_set_clock(struct intel_encoder *encoder,
> struct intel_crtc_state *pipe_config)
> @@ -1343,42 +1535,6 @@ intel_dp_set_clock(struct intel_encoder *encoder,
> }
> }
>
> -static int intersect_rates(const int *source_rates, int source_len,
> - const int *sink_rates, int sink_len,
> - int *common_rates)
> -{
> - int i = 0, j = 0, k = 0;
> -
> - while (i < source_len && j < sink_len) {
> - if (source_rates[i] == sink_rates[j]) {
> - if (WARN_ON(k >= DP_MAX_SUPPORTED_RATES))
> - return k;
> - common_rates[k] = source_rates[i];
> - ++k;
> - ++i;
> - ++j;
> - } else if (source_rates[i] < sink_rates[j]) {
> - ++i;
> - } else {
> - ++j;
> - }
> - }
> - return k;
> -}
> -
> -static int intel_dp_common_rates(struct intel_dp *intel_dp,
> - int *common_rates)
> -{
> - const int *source_rates, *sink_rates;
> - int source_len, sink_len;
> -
> - sink_len = intel_dp_sink_rates(intel_dp, &sink_rates);
> - source_len = intel_dp_source_rates(intel_dp, &source_rates);
> -
> - return intersect_rates(source_rates, source_len,
> - sink_rates, sink_len,
> - common_rates);
> -}
>
> static void snprintf_int_array(char *str, size_t len,
> const int *array, int nelem)
> @@ -1436,6 +1592,9 @@ intel_dp_max_link_rate(struct intel_dp *intel_dp)
> int rates[DP_MAX_SUPPORTED_RATES] = {};
> int len;
>
> + if (intel_dp->max_link_rate_upfront)
> + return intel_dp->max_link_rate_upfront;
> +
> len = intel_dp_common_rates(intel_dp, rates);
> if (WARN_ON(len <= 0))
> return 162000;
> @@ -1488,7 +1647,7 @@ intel_dp_compute_config(struct intel_encoder *encoder,
> enum port port = dp_to_dig_port(intel_dp)->port;
> struct intel_crtc *intel_crtc = to_intel_crtc(pipe_config->base.crtc);
> struct intel_connector *intel_connector = intel_dp->attached_connector;
> - int lane_count, clock;
> + int lane_count, clock = 0;
> int min_lane_count = 1;
> int max_lane_count = intel_dp_max_lane_count(intel_dp);
> /* Conveniently, the link BW constants become indices with a shift...*/
> @@ -1567,11 +1726,24 @@ intel_dp_compute_config(struct intel_encoder *encoder,
> for (; bpp >= 6*3; bpp -= 2*3) {
> mode_rate = intel_dp_link_required(adjusted_mode->crtc_clock,
> bpp);
> + if (!is_edp(intel_dp) && intel_dp->upfront_done) {
> + clock = max_clock;
> + lane_count = intel_dp->max_lanes_upfront;
> + link_clock = intel_dp->max_link_rate_upfront;
> + link_avail = intel_dp_max_data_rate(link_clock,
> + lane_count);
> + mode_rate = intel_dp_link_required(adjusted_mode->crtc_clock,
> + bpp);
> + if (mode_rate <= link_avail)
> + goto found;
> + else
> + continue;
> + }
> +
> for (clock = max_clock; clock >= max_clock; clock--) {
> for (lane_count = max_lane_count;
> lane_count >= min_lane_count;
> lane_count >>= 1) {
> -
> link_clock = common_rates[clock];
> link_avail = intel_dp_max_data_rate(link_clock,
> lane_count);
> @@ -1600,7 +1772,6 @@ found:
> }
>
> pipe_config->lane_count = lane_count;
> -
> pipe_config->pipe_bpp = bpp;
> pipe_config->port_clock = common_rates[clock];
>
> @@ -4284,7 +4455,7 @@ intel_dp_long_pulse(struct intel_connector *intel_connector)
> struct drm_device *dev = connector->dev;
> enum drm_connector_status status;
> enum intel_display_power_domain power_domain;
> - u8 sink_irq_vector = 0;
> + u8 sink_irq_vector;
>
> power_domain = intel_display_port_aux_power_domain(intel_encoder);
> intel_display_power_get(to_i915(dev), power_domain);
> @@ -4377,9 +4548,12 @@ intel_dp_long_pulse(struct intel_connector *intel_connector)
> }
>
> out:
> - if ((status != connector_status_connected) &&
> - (intel_dp->is_mst == false))
> + if (status != connector_status_connected) {
> intel_dp_unset_edid(intel_dp);
> + intel_dp->upfront_done = false;
> + intel_dp->max_lanes_upfront = 0;
> + intel_dp->max_link_rate_upfront = 0;
> + }
>
> intel_display_power_put(to_i915(dev), power_domain);
> return;
> @@ -5623,6 +5797,13 @@ intel_dp_init_connector(struct intel_digital_port *intel_dig_port,
> if (type == DRM_MODE_CONNECTOR_eDP)
> intel_encoder->type = INTEL_OUTPUT_EDP;
>
> + /* Initialize upfront link training vfunc for DP */
> + if (intel_encoder->type != INTEL_OUTPUT_EDP) {
> + if (IS_BROXTON(dev_priv) || IS_SKYLAKE(dev_priv) ||
> + IS_BROADWELL(dev_priv) || IS_HASWELL(dev_priv))
> + intel_dp->upfront_link_train = intel_ddi_link_train;
> + }
> +
> /* eDP only on port B and/or C on vlv/chv */
> if (WARN_ON((IS_VALLEYVIEW(dev) || IS_CHERRYVIEW(dev)) &&
> is_edp(intel_dp) && port != PORT_B && port != PORT_C))
> diff --git a/drivers/gpu/drm/i915/intel_dp_link_training.c b/drivers/gpu/drm/i915/intel_dp_link_training.c
> index f1e08f0..b6f380b 100644
> --- a/drivers/gpu/drm/i915/intel_dp_link_training.c
> +++ b/drivers/gpu/drm/i915/intel_dp_link_training.c
> @@ -304,7 +304,6 @@ intel_dp_link_training_channel_equalization(struct intel_dp *intel_dp)
> intel_dp_set_idle_link_train(intel_dp);
>
> return intel_dp->channel_eq_status;
> -
> }
>
> void intel_dp_stop_link_train(struct intel_dp *intel_dp)
> diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
> index 5b97a7d4..e5ab375 100644
> --- a/drivers/gpu/drm/i915/intel_drv.h
> +++ b/drivers/gpu/drm/i915/intel_drv.h
> @@ -882,6 +882,12 @@ struct intel_dp {
> enum hdmi_force_audio force_audio;
> bool limited_color_range;
> bool color_range_auto;
> +
> + /* Upfront link train parameters */
> + int max_link_rate_upfront;
> + uint8_t max_lanes_upfront;
> + bool upfront_done;
> +
> uint8_t dpcd[DP_RECEIVER_CAP_SIZE];
> uint8_t psr_dpcd[EDP_PSR_RECEIVER_CAP_SIZE];
> uint8_t downstream_ports[DP_MAX_DOWNSTREAM_PORTS];
> @@ -939,6 +945,11 @@ struct intel_dp {
> /* This is called before a link training is starterd */
> void (*prepare_link_retrain)(struct intel_dp *intel_dp);
>
> + /* For Upfront link training */
> + bool (*upfront_link_train)(struct intel_dp *intel_dp, int clock,
> + uint8_t lane_count, bool link_mst,
> + bool is_upfront);
> +
> /* Displayport compliance testing */
> unsigned long compliance_test_type;
> unsigned long compliance_test_data;
> @@ -1161,7 +1172,8 @@ void intel_ddi_clock_get(struct intel_encoder *encoder,
> void intel_ddi_set_vc_payload_alloc(struct drm_crtc *crtc, bool state);
> uint32_t ddi_signal_levels(struct intel_dp *intel_dp);
> bool intel_ddi_link_train(struct intel_dp *intel_dp, int max_link_rate,
> - uint8_t max_lane_count, bool link_mst);
> + uint8_t max_lane_count, bool link_mst,
> + bool is_upfront);
> struct intel_shared_dpll *intel_ddi_get_link_dpll(struct intel_dp *intel_dp,
> int clock);
> unsigned int intel_fb_align_height(struct drm_device *dev,
--
Jani Nikula, Intel Open Source Technology Center
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