On Tue, Jan 25, 2022 at 07:03:43PM +0200, Jani Nikula wrote:
<snip>
> +static bool
> +intel_dp_128b132b_lane_cds(struct intel_dp *intel_dp,
> + const struct intel_crtc_state *crtc_state,
> + int lttpr_count)
> +{
> + struct intel_encoder *encoder = &dp_to_dig_port(intel_dp)->base;
> + struct drm_i915_private *i915 = to_i915(encoder->base.dev);
> + u8 link_status[DP_LINK_STATUS_SIZE];
> + unsigned long deadline;
> +
> + if (drm_dp_dpcd_writeb(&intel_dp->aux, DP_TRAINING_PATTERN_SET,
> + DP_TRAINING_PATTERN_2_CDS) != 1) {
> + drm_err(&i915->drm,
> + "[ENCODER:%d:%s] Failed to start 128b/132b TPS2 CDS\n",
> + encoder->base.base.id, encoder->base.name);
> + return false;
> + }
> +
> + deadline = jiffies + msecs_to_jiffies((lttpr_count + 1) * 20);
> + for (;;) {
> + usleep_range(2000, 3000);
> +
> + if (drm_dp_dpcd_read_link_status(&intel_dp->aux, link_status) <
> 0) {
> + drm_err(&i915->drm,
> + "[ENCODER:%d:%s] Failed to read link status\n",
> + encoder->base.base.id, encoder->base.name);
> + return false;
> + }
> +
> + if (drm_dp_128b132b_cds_interlane_align_done(link_status) &&
> + drm_dp_128b132b_lane_symbol_locked(link_status,
> crtc_state->lane_count)) {
I'm thinkin we want to check for both eq done and symbol locked here,
just like we do with 8b10b.
> + drm_dbg_kms(&i915->drm,
> + "[ENCODER:%d:%s] CDS interlane align
> done\n",
> + encoder->base.base.id, encoder->base.name);
> + break;
> + }
> +
> + if (drm_dp_128b132b_link_training_failed(link_status)) {
> + intel_dp_dump_link_status(intel_dp, DP_PHY_DPRX,
> link_status);
> + drm_err(&i915->drm,
> + "[ENCODER:%d:%s] Downstream link training
> failure\n",
> + encoder->base.base.id, encoder->base.name);
> + return false;
> + }
> +
> + if (time_after(jiffies, deadline)) {
> + intel_dp_dump_link_status(intel_dp, DP_PHY_DPRX,
> link_status);
> + drm_err(&i915->drm,
> + "[ENCODER:%d:%s] CDS timeout\n",
> + encoder->base.base.id, encoder->base.name);
> + return false;
> + }
> + }
> +
> + /* FIXME: Should DP_TRAINING_PATTERN_DISABLE be written first? */
> + if (intel_dp->set_idle_link_train)
> + intel_dp->set_idle_link_train(intel_dp, crtc_state);
> +
> + return true;
> +}
--
Ville Syrjälä
Intel
