On Fri, Sep 9, 2016 at 4:29 PM, Manasi Navare <manasi.d.navare@xxxxxxxxx> wrote:
> 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 we need to train the link before
> modeset. This upfront link training caches the values of max link rate
> and max lane count that get used later during modeset. Upfront link
> training does not change any HW state, the link is disabled and PLL
> values are reset to previous values after upfront link tarining so
> that subsequent modeset is not aware of these changes.
>
> This patch is based on prior work done by
> R,Durgadoss <durgadoss.r@xxxxxxxxx>
>
> Changes since v15:
> * Split this patch into two patches - one with functional
> changes to enable upfront and other with moving the existing
> functions around so that they can be used for upfront (Jani Nikula)
> * Cleaned up the commit message
>
> Signed-off-by: Durgadoss R <durgadoss.r@xxxxxxxxx>
> Signed-off-by: Jim Bride <jim.bride@xxxxxxxxxxxxxxx>
> Signed-off-by: Manasi Navare <manasi.d.navare@xxxxxxxxx>
> ---
> drivers/gpu/drm/i915/intel_ddi.c | 21 ++-
> drivers/gpu/drm/i915/intel_dp.c | 196 +++++++++++++++++++++++++-
> drivers/gpu/drm/i915/intel_dp_link_training.c | 1 -
> drivers/gpu/drm/i915/intel_drv.h | 14 +-
> 4 files changed, 221 insertions(+), 11 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/intel_ddi.c b/drivers/gpu/drm/i915/intel_ddi.c
> index 2c13d0c..2eee5b5 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;
> }
> @@ -2460,7 +2461,7 @@ 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;
> @@ -2509,6 +2510,7 @@ 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);
> @@ -2517,6 +2519,21 @@ 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 429ecf8..18c663d 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 +199,42 @@ 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)
> {
> @@ -274,6 +319,17 @@ static int intel_dp_common_rates(struct intel_dp *intel_dp,
> 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,
> @@ -281,6 +337,92 @@ static int intel_dp_common_rates(struct intel_dp *intel_dp,
> 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)
> @@ -302,6 +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);
>
> @@ -1436,6 +1591,9 @@ 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 +1646,7 @@ 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;
minor, but I believe you don't need this.
> 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...*/
> @@ -1567,6 +1725,21 @@ 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;
> + }
> +
> clock = max_clock;
> lane_count = max_lane_count;
> link_clock = common_rates[clock];
> @@ -1595,7 +1768,6 @@ found:
> }
>
> pipe_config->lane_count = lane_count;
> -
> pipe_config->pipe_bpp = bpp;
> pipe_config->port_clock = common_rates[clock];
>
> @@ -4279,7 +4451,7 @@ 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;
out of context... Why do you need this on this patch?
or separated patch?
>
> power_domain = intel_display_port_aux_power_domain(intel_encoder);
> intel_display_power_get(to_i915(dev), power_domain);
> @@ -4372,9 +4544,12 @@ intel_dp_long_pulse(struct intel_connector *intel_connector)
> }
>
> out:
> - if ((status != connector_status_connected) &&
> - (intel_dp->is_mst == false))
This should be in a separated patch I believe. There is no explanation
why you don't need this for MST
> + 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;
> @@ -5618,6 +5793,13 @@ 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))
This should be HAS_DDI(dev_priv), otherwise we have the risk to forget
a platform, like we are leaving Kabylake behind.
> + 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,
> --
> 1.9.1
>
> _______________________________________________
> Intel-gfx mailing list
> Intel-gfx@xxxxxxxxxxxxxxxxxxxxx
> https://lists.freedesktop.org/mailman/listinfo/intel-gfx
--
Rodrigo Vivi
Blog: http://blog.vivi.eng.br
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