Merge "disp: msm: dp: add support for lane count reduction" (f0d4d74c) · Commits · e / devices / android_kernel_fairphone_FP5

msm/dp/dp_ctrl.c

+41 −2

Original line number	Diff line number	Diff line
		@@ -71,6 +71,8 @@ struct dp_ctrl_private {

		atomic_t aborted;

		u8 initial_lane_count;

		u32 vic;
		u32 stream_count;
		struct dp_mst_channel_info mst_ch_info;
		@@ -254,6 +256,32 @@ static int dp_ctrl_read_link_status(struct dp_ctrl_private *ctrl,
		return ret;
		}

		static int dp_ctrl_lane_count_down_shift(struct dp_ctrl_private *ctrl)
		{
		int ret = -EAGAIN;
		u8 lanes = ctrl->link->link_params.lane_count;

		if (ctrl->panel->link_info.revision != 0x14)
		return -EINVAL;

		switch (lanes) {
		case 4:
		ctrl->link->link_params.lane_count = 2;
		break;
		case 2:
		ctrl->link->link_params.lane_count = 1;
		break;
		default:
		if (lanes != ctrl->initial_lane_count)
		ret = -EINVAL;
		break;
		}

		pr_debug("new lane count=%d\n", ctrl->link->link_params.lane_count);

		return ret;
		}

		static int dp_ctrl_link_train_1(struct dp_ctrl_private *ctrl)
		{
		int tries, old_v_level, ret = 0;
		@@ -416,12 +444,19 @@ static int dp_ctrl_link_training_2(struct dp_ctrl_private *ctrl)
		if (ret)
		break;

		/* check if CR bits still remain set */
		if (!drm_dp_clock_recovery_ok(link_status,
		ctrl->link->link_params.lane_count)) {
		ret = -EINVAL;
		break;
		}

		if (drm_dp_channel_eq_ok(link_status,
		ctrl->link->link_params.lane_count))
		break;

		if (tries > maximum_retries) {
		ret = -ETIMEDOUT;
		ret = dp_ctrl_lane_count_down_shift(ctrl);
		break;
		}
		tries++;
		@@ -604,6 +639,7 @@ static int dp_ctrl_link_setup(struct dp_ctrl_private *ctrl, bool shallow)
		if (!link_train_max_retries-- \|\| atomic_read(&ctrl->aborted))
		break;

		if (rc != -EAGAIN)
		dp_ctrl_link_rate_down_shift(ctrl);

		dp_ctrl_configure_source_link_params(ctrl, false);
		@@ -1176,6 +1212,9 @@ static int dp_ctrl_on(struct dp_ctrl *dp_ctrl, bool mst_mode,
		ctrl->link->link_params.bw_code,
		ctrl->link->link_params.lane_count);

		/* backup initial lane count */
		ctrl->initial_lane_count = ctrl->link->link_params.lane_count;

		rc = dp_ctrl_link_setup(ctrl, shallow);
		ctrl->power_on = true;
		end: