67fba3f1c7
The DP PHY vswing/pre-emphasis level programming the driver does is
related to the DPTX -> first LTTPR link segment only. Accordingly it
should be only programmed when link training the first LTTPR and kept
as-is when training subsequent LTTPRs and the DPRX. For these latter
PHYs the vs/pe levels will be set in response to writing the
DP_TRAINING_LANEx_SET_PHY_REPEATERy DPCD registers (by an upstream LTTPR
TX PHY snooping this write access of its downstream LTTPR/DPRX RX PHY).
The above is also described in DP Standard v2.0 under 3.6.6.1.
While at it simplify and add the LTTPR that is link trained to the debug
message in intel_dp_set_signal_levels().
Fixes: b30edfd8d0b4 ("drm/i915: Switch to LTTPR non-transparent mode link training")
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Imre Deak <imre.deak@intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20201229172201.4155327-2-imre.deak@intel.com
35 lines
1.1 KiB
C
35 lines
1.1 KiB
C
/* SPDX-License-Identifier: MIT */
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/*
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* Copyright © 2019 Intel Corporation
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*/
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#ifndef __INTEL_DP_LINK_TRAINING_H__
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#define __INTEL_DP_LINK_TRAINING_H__
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#include <drm/drm_dp_helper.h>
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struct intel_crtc_state;
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struct intel_dp;
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int intel_dp_lttpr_init(struct intel_dp *intel_dp);
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void intel_dp_get_adjust_train(struct intel_dp *intel_dp,
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const struct intel_crtc_state *crtc_state,
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enum drm_dp_phy dp_phy,
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const u8 link_status[DP_LINK_STATUS_SIZE]);
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void intel_dp_set_signal_levels(struct intel_dp *intel_dp,
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const struct intel_crtc_state *crtc_state,
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enum drm_dp_phy dp_phy);
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void intel_dp_start_link_train(struct intel_dp *intel_dp,
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const struct intel_crtc_state *crtc_state);
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void intel_dp_stop_link_train(struct intel_dp *intel_dp,
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const struct intel_crtc_state *crtc_state);
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/* Get the TPSx symbol type of the value programmed to DP_TRAINING_PATTERN_SET */
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static inline u8 intel_dp_training_pattern_symbol(u8 pattern)
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{
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return pattern & ~DP_LINK_SCRAMBLING_DISABLE;
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}
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#endif /* __INTEL_DP_LINK_TRAINING_H__ */
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