Re: [PATCH v3 2/3] Subject: [PATCH] drm/mediatek/dp: Add HDCP2.x feature for DisplayPort

["CK Hu (胡俊光)" <ck.hu@mediatek.com>]

Hi, Mac:

On Sat, 2024-06-08 at 20:01 +0800, mac.shen wrote:
> Changes in v3:
> - refine the function to get system time
> - refine the flow to do HDCP with content type and
>   protection value which set by user space
> - refine the flow to update content protection
> - refine the flow to do HDCP2.x authentication
> per suggestion from the previous thread:
> https://urldefense.com/v3/__https://patchwork.kernel.org/project/linux-mediatek__;!!CTRNKA9wMg0ARbw!md6xUiYN88D2YmETs8FQgaExM2zH8S1SmAEU9GRchwpNsXOyDFul3ziVKhRpCJaj8Rcn-gvM-801runjwA$ 
> /patch/20240205055055.25340-3-mac.shen@mediatek.com/
> 
> Signed-off-by: mac.shen <mac.shen@mediatek.com>
> ---

[snip]

> +
> +static int dp_tx_hdcp2x_read_rep_send_recvid_list(struct mtk_hdcp_info *hdcp_info)
> +{
> +	struct mtk_dp *mtk_dp = container_of(hdcp_info, struct mtk_dp, hdcp_info);
> +	u8 rx_status = 0;
> +	ssize_t ret;
> +
> +	dev_dbg(mtk_dp->dev, "[HDCP2.X] HDCP_2_2_REP_SEND_RECVID_LIST\n");
> +
> +	dp_tx_hdcp2x_wait_for_cp_irq(hdcp_info, HDCP_2_2_RECVID_LIST_TIMEOUT_MS);
> +	hdcp_info->hdcp2_info.cp_irq_cached = atomic_read(&hdcp_info->hdcp2_info.cp_irq);
> +
> +	ret = drm_dp_dpcd_read(&mtk_dp->aux, DP_HDCP_2_2_REG_RXSTATUS_OFFSET, &rx_status,
> +			       HDCP_2_2_DP_RXSTATUS_LEN);
> +	if (ret != HDCP_2_2_DP_RXSTATUS_LEN)
> +		return ret >= 0 ? -EIO : ret;
> +
> +	if (!HDCP_2_2_DP_RXSTATUS_READY(rx_status)) {
> +		dev_err(mtk_dp->dev, "[HDCP2.X] RX status no ready\n");
> +		return -EAGAIN;

In [1], intel return -ETIMEOUT and not retry. Maybe return -ETIMEOUT is better?

[1] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/drivers/gpu/drm/i915/display/intel_dp_hdcp.c?h=v6.12-rc5#n428

Regards,
CK

> +	}
> +
> +	ret = drm_dp_dpcd_read(&mtk_dp->aux, DP_HDCP_2_2_REP_SEND_RECVID_LIST_OFFSET,
> +			       hdcp_info->hdcp2_info.hdcp_rx.recvid_list.rx_info,
> +		HDCP_2_2_RXINFO_LEN);
> +	if (ret < 0)
> +		return ret;
> +
> +	hdcp_info->hdcp2_info.device_count =
> +	(HDCP_2_2_DEV_COUNT_HI(hdcp_info->hdcp2_info.hdcp_rx.recvid_list.rx_info[0]) << 4 |
> +	HDCP_2_2_DEV_COUNT_LO(hdcp_info->hdcp2_info.hdcp_rx.recvid_list.rx_info[1]));
> +
> +	ret = drm_dp_dpcd_read(&mtk_dp->aux, DP_HDCP_2_2_REG_SEQ_NUM_V_OFFSET,
> +			       hdcp_info->hdcp2_info.hdcp_rx.recvid_list.seq_num_v,
> +		HDCP_2_2_SEQ_NUM_LEN);
> +	if (ret < 0)
> +		return ret;
> +
> +	ret = drm_dp_dpcd_read(&mtk_dp->aux, DP_HDCP_2_2_REG_VPRIME_OFFSET,
> +			       hdcp_info->hdcp2_info.hdcp_rx.recvid_list.v_prime,
> +		HDCP_2_2_V_PRIME_HALF_LEN);
> +	if (ret < 0)
> +		return ret;
> +
> +	ret = drm_dp_dpcd_read(&mtk_dp->aux, DP_HDCP_2_2_REG_RECV_ID_LIST_OFFSET,
> +			       hdcp_info->hdcp2_info.hdcp_rx.recvid_list.receiver_ids,
> +		hdcp_info->hdcp2_info.device_count * HDCP_2_2_RECEIVER_ID_LEN);
> +	if (ret < 0)
> +		return ret;
> +
> +	return 0;
> +}
> +