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_enable_auth(struct mtk_hdcp_info *hdcp_info, bool enable)
> +{
> +	struct mtk_dp *mtk_dp = container_of(hdcp_info, struct mtk_dp, hdcp_info);
> +	u32 version;
> +	int ret;
> +
> +	dp_tx_hdcp2x_set_auth_pass(hdcp_info, enable);
> +	if (!enable) {
> +		ret = tee_hdcp_enable_encrypt(hdcp_info, enable, HDCP_NONE);
> +		if (ret)
> +			return ret;
> +		mtk_dp_update_bits(mtk_dp, MTK_DP_ENC0_P0_3000, 0, HDCP_FRAME_EN_DP_ENC0_P0);
> +
> +		return 0;
> +	}
> +
> +	if (HDCP_2_2_HDCP1_DEVICE_CONNECTED(hdcp_info->hdcp2_info.hdcp_rx.recvid_list.rx_info[1]))
> +		version = HDCP_V1;

dp_tx_hdcp2x_enable_auth() is called only when HDCP 2.x, but here detect that version is 1.
I don't know the specification of HDCP, is this is an error case?
Or if this is a normal case, please add some comment here to explain for someone who don't know HDCP specification.

Regards,
CK

> +	else if (HDCP_2_2_HDCP_2_0_REP_CONNECTED
> +		(hdcp_info->hdcp2_info.hdcp_rx.recvid_list.rx_info[1]))
> +		version = HDCP_V2;
> +	else
> +		version = HDCP_V2_3;
> +
> +	ret = tee_hdcp_enable_encrypt(hdcp_info, enable, version);
> +	if (ret)
> +		return ret;
> +	mtk_dp_update_bits(mtk_dp, MTK_DP_ENC0_P0_3000,
> +			   HDCP_FRAME_EN_DP_ENC0_P0, HDCP_FRAME_EN_DP_ENC0_P0);
> +
> +	return 0;
> +}
> +