Re: [PATCH 3/7] drm/msm/dp: Remove dead code related to downstream cap info

[Kuogee Hsieh]

On 8/29/2023 11:47 AM, Stephen Boyd wrote:
> We read the downstream port count and capability info but never use it
> anywhere. Remove 'ds_port_cnt' and 'ds_cap_info' and any associated code
> from this driver. Fold the check for 'dfp_present' into a call to
> drm_dp_is_branch() at the one place it is used to get rid of any member
> storage related to downstream ports.
>
> Cc: Vinod Polimera <quic_vpolimer@xxxxxxxxxxx>
> Cc: Kuogee Hsieh <quic_khsieh@xxxxxxxxxxx>
> Signed-off-by: Stephen Boyd <swboyd@xxxxxxxxxxxx>
Tested-by: Kuogee Hsieh <quic_khsieh@xxxxxxxxxxx>
Reviewed-by: Kuogee Hsieh <quic_khsieh@xxxxxxxxxxx>
> ---
>   drivers/gpu/drm/msm/dp/dp_panel.c | 25 +++----------------------
>   drivers/gpu/drm/msm/dp/dp_panel.h |  6 ------
>   2 files changed, 3 insertions(+), 28 deletions(-)
>
> diff --git a/drivers/gpu/drm/msm/dp/dp_panel.c b/drivers/gpu/drm/msm/dp/dp_panel.c
> index a0523b18b9e9..9fb4e963fefb 100644
> --- a/drivers/gpu/drm/msm/dp/dp_panel.c
> +++ b/drivers/gpu/drm/msm/dp/dp_panel.c
> @@ -43,9 +43,7 @@ static void dp_panel_read_psr_cap(struct dp_panel_private *panel)
>   
>   static int dp_panel_read_dpcd(struct dp_panel *dp_panel)
>   {
> -	int rc = 0;
> -	size_t len;
> -	ssize_t rlen;
> +	int rc;
>   	struct dp_panel_private *panel;
>   	struct dp_link_info *link_info;
>   	u8 *dpcd, major, minor;
> @@ -79,25 +77,8 @@ static int dp_panel_read_dpcd(struct dp_panel *dp_panel)
>   	if (drm_dp_enhanced_frame_cap(dpcd))
>   		link_info->capabilities |= DP_LINK_CAP_ENHANCED_FRAMING;
>   
> -	dp_panel->dfp_present = dpcd[DP_DOWNSTREAMPORT_PRESENT];
> -	dp_panel->dfp_present &= DP_DWN_STRM_PORT_PRESENT;
> -
> -	if (dp_panel->dfp_present && (dpcd[DP_DPCD_REV] > 0x10)) {
> -		dp_panel->ds_port_cnt = dpcd[DP_DOWN_STREAM_PORT_COUNT];
> -		dp_panel->ds_port_cnt &= DP_PORT_COUNT_MASK;
> -		len = DP_DOWNSTREAM_PORTS * DP_DOWNSTREAM_CAP_SIZE;
> -
> -		rlen = drm_dp_dpcd_read(panel->aux,
> -			DP_DOWNSTREAM_PORT_0, dp_panel->ds_cap_info, len);
> -		if (rlen < len) {
> -			DRM_ERROR("ds port status failed, rlen=%zd\n", rlen);
> -			rc = -EINVAL;
> -			goto end;
> -		}
> -	}
> -
>   	dp_panel_read_psr_cap(panel);
> -end:
> +
>   	return rc;
>   }
>   
> @@ -173,7 +154,7 @@ int dp_panel_read_sink_caps(struct dp_panel *dp_panel,
>   		return -EINVAL;
>   	}
>   
> -	if (dp_panel->dfp_present) {
> +	if (drm_dp_is_branch(dp_panel->dpcd)) {
>   		count = drm_dp_read_sink_count(panel->aux);
>   		if (!count) {
>   			DRM_ERROR("no downstream ports connected\n");
> diff --git a/drivers/gpu/drm/msm/dp/dp_panel.h b/drivers/gpu/drm/msm/dp/dp_panel.h
> index 6d733480a62d..3cb1f8dcfd3b 100644
> --- a/drivers/gpu/drm/msm/dp/dp_panel.h
> +++ b/drivers/gpu/drm/msm/dp/dp_panel.h
> @@ -13,9 +13,6 @@
>   
>   struct edid;
>   
> -#define DP_DOWNSTREAM_PORTS		4
> -#define DP_DOWNSTREAM_CAP_SIZE		4
> -
>   struct dp_display_mode {
>   	struct drm_display_mode drm_mode;
>   	u32 capabilities;
> @@ -39,9 +36,6 @@ struct dp_panel_psr {
>   struct dp_panel {
>   	/* dpcd raw data */
>   	u8 dpcd[DP_RECEIVER_CAP_SIZE];
> -	u8 ds_cap_info[DP_DOWNSTREAM_PORTS * DP_DOWNSTREAM_CAP_SIZE];
> -	u32 ds_port_cnt;
> -	u32 dfp_present;
>   
>   	struct dp_link_info link_info;
>   	struct drm_dp_desc desc;