On Fri, Dec 18, 2020 at 04:07:17PM +0530, Ankit Nautiyal wrote:
> This patch adds functions to start FRL training for an HDMI2.1 sink,
> connected via a PCON as a DP branch device.
> This patch also adds a new structure for storing frl training related
> data, when FRL training is completed.
>
> v2: As suggested by Uma Shankar:
> -renamed couple of variables for better clarity
> -tweaked the macros used for correct semantics for true/false
> -fixed other styling issues.
>
> v3: Completed the TODO for condition for going to FRL mode.
> Modified the condition to determine the required FRL b/w
> based only on the Pcon and Sink's max FRL values.
> Moved the frl structure initialization to intel_dp_init_connector().
>
> v4: Fixed typo in initialization of frl structure.
>
> v5: Always use FRL if its possible, instead of enabling only for
> higher modes as done in v3.
>
> Signed-off-by: Ankit Nautiyal <ankit.k.nauti...@intel.com>
> Reviewed-by: Uma Shankar <uma.shan...@intel.com> (v2)
> ---
> .../drm/i915/display/intel_display_types.h | 7 +
> drivers/gpu/drm/i915/display/intel_dp.c | 151 ++++++++++++++++++
> drivers/gpu/drm/i915/display/intel_dp.h | 2 +
> 3 files changed, 160 insertions(+)
<snip>
> diff --git a/drivers/gpu/drm/i915/display/intel_dp.c
> b/drivers/gpu/drm/i915/display/intel_dp.c
> index 0596d6c24e73..43027a6d5e5e 100644
> --- a/drivers/gpu/drm/i915/display/intel_dp.c
> +++ b/drivers/gpu/drm/i915/display/intel_dp.c
> @@ -3891,6 +3891,8 @@ static void intel_disable_dp(struct intel_atomic_state
> *state,
> intel_edp_backlight_off(old_conn_state);
> intel_dp_set_power(intel_dp, DP_SET_POWER_D3);
> intel_edp_panel_off(intel_dp);
> + intel_dp->frl.is_trained = false;
> + intel_dp->frl.trained_rate_gbps = 0;
This stuff looks rather misplaced (or missing from elsewhere). This code
doesn't even get executed on modern platforms.
<snip>
> +static int intel_dp_pcon_start_frl_training(struct intel_dp *intel_dp)
> +{
> +#define PCON_EXTENDED_TRAIN_MODE (1 > 0)
> +#define PCON_CONCURRENT_MODE (1 > 0)
> +#define PCON_SEQUENTIAL_MODE !PCON_CONCURRENT_MODE
> +#define PCON_NORMAL_TRAIN_MODE !PCON_EXTENDED_TRAIN_MODE
All of that looks like nonsense. What is it supposed to do?
> +#define TIMEOUT_FRL_READY_MS 500
> +#define TIMEOUT_HDMI_LINK_ACTIVE_MS 1000
> +
> + struct drm_i915_private *i915 = dp_to_i915(intel_dp);
> + int max_frl_bw, max_pcon_frl_bw, max_edid_frl_bw, ret;
> + u8 max_frl_bw_mask = 0, frl_trained_mask;
> + bool is_active;
> +
> + ret = drm_dp_pcon_reset_frl_config(&intel_dp->aux);
> + if (ret < 0)
> + return ret;
> +
> + max_pcon_frl_bw = intel_dp->dfp.pcon_max_frl_bw;
> + drm_dbg(&i915->drm, "PCON max rate = %d Gbps\n", max_pcon_frl_bw);
> +
> + max_edid_frl_bw = intel_dp_hdmi_sink_max_frl(intel_dp);
> + drm_dbg(&i915->drm, "Sink max rate from EDID = %d Gbps\n",
> max_edid_frl_bw);
> +
> + max_frl_bw = min(max_edid_frl_bw, max_pcon_frl_bw);
> +
> + if (max_frl_bw <= 0)
> + return -EINVAL;
> +
> + ret = drm_dp_pcon_frl_prepare(&intel_dp->aux, false);
> + if (ret < 0)
> + return ret;
> + /* Wait for PCON to be FRL Ready */
> + wait_for(is_active = drm_dp_pcon_is_frl_ready(&intel_dp->aux) == true,
> TIMEOUT_FRL_READY_MS);
> +
> + if (!is_active)
> + return -ETIMEDOUT;
> +
> + max_frl_bw_mask = intel_dp_pcon_set_frl_mask(max_frl_bw);
> + ret = drm_dp_pcon_frl_configure_1(&intel_dp->aux, max_frl_bw,
> PCON_SEQUENTIAL_MODE);
> + if (ret < 0)
> + return ret;
> + ret = drm_dp_pcon_frl_configure_2(&intel_dp->aux, max_frl_bw_mask,
> PCON_NORMAL_TRAIN_MODE);
> + if (ret < 0)
> + return ret;
> + ret = drm_dp_pcon_frl_enable(&intel_dp->aux);
> + if (ret < 0)
> + return ret;
> + /*
> + * Wait for FRL to be completed
> + * Check if the HDMI Link is up and active.
> + */
> + wait_for(is_active = drm_dp_pcon_hdmi_link_active(&intel_dp->aux) ==
> true, TIMEOUT_HDMI_LINK_ACTIVE_MS);
> +
> + if (!is_active)
> + return -ETIMEDOUT;
> +
> + /* Verify HDMI Link configuration shows FRL Mode */
> + if (DP_PCON_HDMI_MODE_FRL != drm_dp_pcon_hdmi_link_mode(&intel_dp->aux,
> &frl_trained_mask)) {
> + drm_dbg(&i915->drm, "HDMI couldn't be trained in FRL Mode\n");
> + return -EINVAL;
> + }
> + drm_dbg(&i915->drm, "MAX_FRL_MASK = %u, FRL_TRAINED_MASK = %u\n",
> max_frl_bw_mask, frl_trained_mask);
> +
> + intel_dp->frl.trained_rate_gbps =
> intel_dp_pcon_get_frl_mask(frl_trained_mask);
> + intel_dp->frl.is_trained = true;
> + drm_dbg(&i915->drm, "FRL trained with : %d Gbps\n",
> intel_dp->frl.trained_rate_gbps);
> +
> + return 0;
> +}
> +
> +static bool intel_dp_is_hdmi_2_1_sink(struct intel_dp *intel_dp)
> +{
> + if (drm_dp_is_branch(intel_dp->dpcd) &&
> + intel_dp->has_hdmi_sink &&
> + intel_dp_hdmi_sink_max_frl(intel_dp) > 0)
> + return true;
> +
> + return false;
> +}
> +
> +void intel_dp_check_frl_training(struct intel_dp *intel_dp)
> +{
> + struct drm_i915_private *dev_priv = dp_to_i915(intel_dp);
> +
> + /* Always go for FRL training if supported */
> + if (!intel_dp_is_hdmi_2_1_sink(intel_dp) ||
> + intel_dp->frl.is_trained)
> + return;
> +
> + if (intel_dp_pcon_start_frl_training(intel_dp) < 0) {
> + int ret, mode;
> +
> + drm_dbg(&dev_priv->drm, "Couldnt set FRL mode, continuing with
> TMDS mode\n");
> + ret = drm_dp_pcon_reset_frl_config(&intel_dp->aux);
> + mode = drm_dp_pcon_hdmi_link_mode(&intel_dp->aux, NULL);
> +
> + if (ret < 0 || mode != DP_PCON_HDMI_MODE_TMDS)
> + drm_dbg(&dev_priv->drm, "Issue with PCON, cannot set
> TMDS mode\n");
> + } else {
> + drm_dbg(&dev_priv->drm, "FRL training Completed\n");
> + }
> +}
> +
> static void
> g4x_set_link_train(struct intel_dp *intel_dp,
> const struct intel_crtc_state *crtc_state,
> @@ -8210,6 +8358,9 @@ intel_dp_init_connector(struct intel_digital_port
> *dig_port,
> (temp & ~0xf) | 0xd);
> }
>
> + intel_dp->frl.is_trained = false;
> + intel_dp->frl.trained_rate_gbps = 0;
> +
> return true;
>
> fail:
> diff --git a/drivers/gpu/drm/i915/display/intel_dp.h
> b/drivers/gpu/drm/i915/display/intel_dp.h
> index b871a09b6901..58b76a20459c 100644
> --- a/drivers/gpu/drm/i915/display/intel_dp.h
> +++ b/drivers/gpu/drm/i915/display/intel_dp.h
> @@ -144,4 +144,6 @@ bool intel_dp_initial_fastset_check(struct intel_encoder
> *encoder,
> void intel_dp_sync_state(struct intel_encoder *encoder,
> const struct intel_crtc_state *crtc_state);
>
> +void intel_dp_check_frl_training(struct intel_dp *intel_dp);
> +
> #endif /* __INTEL_DP_H__ */
> --
> 2.17.1
--
Ville Syrjälä
Intel
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