linux-kernel - Re: [PATCH v6 2/4] drm/msm/dp: parser data-lanes as property of dp

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <50405292-d6c1-d9ee-20fe-46f4feee6d9c@linaro.org>
Date:   Thu, 1 Dec 2022 01:58:12 +0200
From:   Dmitry Baryshkov <dmitry.baryshkov@...aro.org>
To:     Kuogee Hsieh <quic_khsieh@...cinc.com>,
        dri-devel@...ts.freedesktop.org, robdclark@...il.com,
        sean@...rly.run, swboyd@...omium.org, dianders@...omium.org,
        vkoul@...nel.org, daniel@...ll.ch, airlied@...ux.ie,
        agross@...nel.org, bjorn.andersson@...aro.org
Cc:     quic_abhinavk@...cinc.com, quic_sbillaka@...cinc.com,
        freedreno@...ts.freedesktop.org, linux-arm-msm@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH v6 2/4] drm/msm/dp: parser data-lanes as property of
 dp_out endpoint

On 01/12/2022 01:51, Kuogee Hsieh wrote:
> Add capability to parser data-lanes as property of dp_out endpoint.
> Also retain the original capability to parser data-lanes as property
> of mdss_dp node to handle legacy case.
> 
> Changes in v6:
> -- first patch after split parser patch into two
> 
> Signed-off-by: Kuogee Hsieh <quic_khsieh@...cinc.com>
> ---
>   drivers/gpu/drm/msm/dp/dp_parser.c | 30 +++++++++++++++++++++++-------
>   1 file changed, 23 insertions(+), 7 deletions(-)
> 
> diff --git a/drivers/gpu/drm/msm/dp/dp_parser.c b/drivers/gpu/drm/msm/dp/dp_parser.c
> index dd73221..b06ff60 100644
> --- a/drivers/gpu/drm/msm/dp/dp_parser.c
> +++ b/drivers/gpu/drm/msm/dp/dp_parser.c
> @@ -94,16 +94,32 @@ static int dp_parser_ctrl_res(struct dp_parser *parser)
>   static int dp_parser_misc(struct dp_parser *parser)
>   {
>   	struct device_node *of_node = parser->pdev->dev.of_node;
> -	int len;
> +	struct device_node *endpoint;
> +	int cnt;
> +
> +	/*
> +	 * legacy code, data-lanes is the property of mdss_dp node
> +	 */
> +	cnt = drm_of_get_data_lanes_count(of_node, 1, DP_MAX_NUM_DP_LANES);
> +	if (cnt > 0) {
> +		parser->max_dp_lanes = cnt;
> +		return 0;
> +	}
>   
> -	len = drm_of_get_data_lanes_count(of_node, 1, DP_MAX_NUM_DP_LANES);
> -	if (len < 0) {
> -		DRM_WARN("Invalid property \"data-lanes\", default max DP lanes = %d\n",
> -			 DP_MAX_NUM_DP_LANES);
> -		len = DP_MAX_NUM_DP_LANES;
> +	/*
> +	 * data-lanes is the property of dp_out endpoint
> +	 */
> +	endpoint = of_graph_get_endpoint_by_regs(of_node, 1, 0); /* port@1 */
> +	if (endpoint) {
> +		cnt = of_property_count_u32_elems(endpoint, "data-lanes");

drm_of_get_data_lanes_count(), or better drm_of_get_data_lanes_count_ep().

Also please check new property first, then check the legacy one.

So it would be:

cnt = drm_of_get_data_lanes_count_ep();
if (cnt < 0)
     cnt = drm_of_get_data_lanes_count();
if (cnt < 0) {
     DRM_WARN(...);
     cnt = DP_MAX_NUM_DP_LANES;
}


> +		if (cnt < 0)
> +			parser->max_dp_lanes = DP_MAX_NUM_DP_LANES; /* 4 lanes */
> +		else
> +			parser->max_dp_lanes = cnt;
> +	} else {
> +		parser->max_dp_lanes = DP_MAX_NUM_DP_LANES; /* 4 lanes */
>   	}
>   
> -	parser->max_dp_lanes = len;
>   	return 0;
>   }
>   

-- 
With best wishes
Dmitry