[PATCH v2 07/18] drm/dp: Pimp drm_dp_downstream_max_bpc()

Lyude Paul lyude at redhat.com
Tue Sep 8 17:32:01 UTC 2020


On Fri, 2020-09-04 at 14:53 +0300, Ville Syrjala wrote:
> From: Ville Syrjälä <ville.syrjala at linux.intel.com>
> 
> Deal with more cases in drm_dp_downstream_max_bpc():
> - DPCD 1.0 -> assume 8bpc for non-DP
> - DPCD 1.1+ DP (or DP++ with DP sink) -> allow anything
> - DPCD 1.1+ TMDS -> check the caps, assume 8bpc if the value is crap
> - anything else -> assume 8bpc
> 
> Signed-off-by: Ville Syrjälä <ville.syrjala at linux.intel.com>
> ---
>  drivers/gpu/drm/drm_dp_helper.c               | 69 +++++++++++--------
>  .../drm/i915/display/intel_display_debugfs.c  |  3 +-
>  drivers/gpu/drm/i915/display/intel_dp.c       |  2 +-
>  include/drm/drm_dp_helper.h                   | 10 ++-
>  4 files changed, 51 insertions(+), 33 deletions(-)
> 
> diff --git a/drivers/gpu/drm/drm_dp_helper.c
> b/drivers/gpu/drm/drm_dp_helper.c
> index 0fcb94f7dbe5..ab87209c25d8 100644
> --- a/drivers/gpu/drm/drm_dp_helper.c
> +++ b/drivers/gpu/drm/drm_dp_helper.c
> @@ -653,36 +653,44 @@ int drm_dp_downstream_max_clock(const u8
> dpcd[DP_RECEIVER_CAP_SIZE],
>  EXPORT_SYMBOL(drm_dp_downstream_max_clock);
>  
>  /**
> - * drm_dp_downstream_max_bpc() - extract branch device max
> - *                               bits per component
> - * @dpcd: DisplayPort configuration data
> - * @port_cap: port capabilities
> - *
> - * See also:
> - * drm_dp_read_downstream_info()
> - * drm_dp_downstream_max_clock()
> - *
> - * Returns: Max bpc on success or 0 if max bpc not defined
> - */
> +  * drm_dp_downstream_max_bpc() - extract downstream facing port max
> +  *                               bits per component
> +  * @dpcd: DisplayPort configuration data
> +  * @port_cap: downstream facing port capabilities
> +  * @edid: EDID
> +  *
> +  * Returns max bpc on success or 0 if max bpc not defined

s/Returns/Returns:/

> +  */
>  int drm_dp_downstream_max_bpc(const u8 dpcd[DP_RECEIVER_CAP_SIZE],
> -			      const u8 port_cap[4])
> +			      const u8 port_cap[4],
> +			      const struct edid *edid)
>  {
> -	int type = port_cap[0] & DP_DS_PORT_TYPE_MASK;
> -	bool detailed_cap_info = dpcd[DP_DOWNSTREAMPORT_PRESENT] &
> -		DP_DETAILED_CAP_INFO_AVAILABLE;
> -	int bpc;
> -
> -	if (!detailed_cap_info)
> +	if (!drm_dp_is_branch(dpcd))
>  		return 0;
>  
> -	switch (type) {
> -	case DP_DS_PORT_TYPE_VGA:
> -	case DP_DS_PORT_TYPE_DVI:
> -	case DP_DS_PORT_TYPE_HDMI:
> +	if (dpcd[DP_DPCD_REV] < 0x11) {
> +		switch (dpcd[DP_DOWNSTREAMPORT_PRESENT] &
> DP_DWN_STRM_PORT_TYPE_MASK) {
> +		case DP_DWN_STRM_PORT_TYPE_DP:
> +			return 0;
> +		default:
> +			return 8;
> +		}
> +	}
> +
> +	switch (port_cap[0] & DP_DS_PORT_TYPE_MASK) {
> +	case DP_DS_PORT_TYPE_DP:
> +		return 0;
>  	case DP_DS_PORT_TYPE_DP_DUALMODE:
> -		bpc = port_cap[2] & DP_DS_MAX_BPC_MASK;
> +		if (is_edid_digital_input_dp(edid))
> +			return 0;
> +		fallthrough;
> +	case DP_DS_PORT_TYPE_HDMI:
> +	case DP_DS_PORT_TYPE_DVI:
> +	case DP_DS_PORT_TYPE_VGA:
> +		if ((dpcd[DP_DOWNSTREAMPORT_PRESENT] &
> DP_DETAILED_CAP_INFO_AVAILABLE) == 0)
> +			return 8;
>  
> -		switch (bpc) {
> +		switch (port_cap[2] & DP_DS_MAX_BPC_MASK) {
>  		case DP_DS_8BPC:
>  			return 8;
>  		case DP_DS_10BPC:
> @@ -691,10 +699,12 @@ int drm_dp_downstream_max_bpc(const u8
> dpcd[DP_RECEIVER_CAP_SIZE],
>  			return 12;
>  		case DP_DS_16BPC:
>  			return 16;
> +		default:
> +			return 8;
>  		}
> -		fallthrough;
> +		break;
>  	default:
> -		return 0;
> +		return 8;
>  	}
>  }
>  EXPORT_SYMBOL(drm_dp_downstream_max_bpc);
> @@ -717,12 +727,15 @@ EXPORT_SYMBOL(drm_dp_downstream_id);
>   * @m: pointer for debugfs file
>   * @dpcd: DisplayPort configuration data
>   * @port_cap: port capabilities
> + * @edid: EDID
>   * @aux: DisplayPort AUX channel
>   *
>   */
>  void drm_dp_downstream_debug(struct seq_file *m,
>  			     const u8 dpcd[DP_RECEIVER_CAP_SIZE],
> -			     const u8 port_cap[4], struct drm_dp_aux *aux)
> +			     const u8 port_cap[4],
> +			     const struct edid *edid,
> +			     struct drm_dp_aux *aux)
>  {
>  	bool detailed_cap_info = dpcd[DP_DOWNSTREAMPORT_PRESENT] &
>  				 DP_DETAILED_CAP_INFO_AVAILABLE;
> @@ -789,7 +802,7 @@ void drm_dp_downstream_debug(struct seq_file *m,
>  				seq_printf(m, "\t\tMax TMDS clock: %d kHz\n",
> clk);
>  		}
>  
> -		bpc = drm_dp_downstream_max_bpc(dpcd, port_cap);
> +		bpc = drm_dp_downstream_max_bpc(dpcd, port_cap, edid);
>  
>  		if (bpc > 0)
>  			seq_printf(m, "\t\tMax bpc: %d\n", bpc);
> diff --git a/drivers/gpu/drm/i915/display/intel_display_debugfs.c
> b/drivers/gpu/drm/i915/display/intel_display_debugfs.c
> index 53a0a3d9a22d..0bf31f9a8af5 100644
> --- a/drivers/gpu/drm/i915/display/intel_display_debugfs.c
> +++ b/drivers/gpu/drm/i915/display/intel_display_debugfs.c
> @@ -626,6 +626,7 @@ static void intel_dp_info(struct seq_file *m,
>  {
>  	struct intel_encoder *intel_encoder =
> intel_attached_encoder(intel_connector);
>  	struct intel_dp *intel_dp = enc_to_intel_dp(intel_encoder);
> +	const struct drm_property_blob *edid = intel_connector-
> >base.edid_blob_ptr;
>  
>  	seq_printf(m, "\tDPCD rev: %x\n", intel_dp->dpcd[DP_DPCD_REV]);
>  	seq_printf(m, "\taudio support: %s\n", yesno(intel_dp->has_audio));
> @@ -633,7 +634,7 @@ static void intel_dp_info(struct seq_file *m,
>  		intel_panel_info(m, &intel_connector->panel);
>  
>  	drm_dp_downstream_debug(m, intel_dp->dpcd, intel_dp->downstream_ports,
> -				&intel_dp->aux);
> +				edid ? edid->data : NULL, &intel_dp->aux);
>  }
>  
>  static void intel_dp_mst_info(struct seq_file *m,
> diff --git a/drivers/gpu/drm/i915/display/intel_dp.c
> b/drivers/gpu/drm/i915/display/intel_dp.c
> index 2c8e82d97a34..c73b3efd84e0 100644
> --- a/drivers/gpu/drm/i915/display/intel_dp.c
> +++ b/drivers/gpu/drm/i915/display/intel_dp.c
> @@ -6071,7 +6071,7 @@ intel_dp_set_edid(struct intel_dp *intel_dp)
>  
>  	intel_dp->dfp.max_bpc =
>  		drm_dp_downstream_max_bpc(intel_dp->dpcd,
> -					  intel_dp->downstream_ports);
> +					  intel_dp->downstream_ports, edid);
>  
>  	drm_dbg_kms(&i915->drm, "[CONNECTOR:%d:%s] DFP max bpc %d\n",
>  		    connector->base.base.id, connector->base.name,
> diff --git a/include/drm/drm_dp_helper.h b/include/drm/drm_dp_helper.h
> index 4f946826dfce..6218de1294c1 100644
> --- a/include/drm/drm_dp_helper.h
> +++ b/include/drm/drm_dp_helper.h
> @@ -1646,10 +1646,14 @@ bool drm_dp_downstream_is_tmds(const u8
> dpcd[DP_RECEIVER_CAP_SIZE],
>  int drm_dp_downstream_max_clock(const u8 dpcd[DP_RECEIVER_CAP_SIZE],
>  				const u8 port_cap[4]);
>  int drm_dp_downstream_max_bpc(const u8 dpcd[DP_RECEIVER_CAP_SIZE],
> -			      const u8 port_cap[4]);
> +			      const u8 port_cap[4],
> +			      const struct edid *edid);
>  int drm_dp_downstream_id(struct drm_dp_aux *aux, char id[6]);
> -void drm_dp_downstream_debug(struct seq_file *m, const u8
> dpcd[DP_RECEIVER_CAP_SIZE],
> -			     const u8 port_cap[4], struct drm_dp_aux *aux);
> +void drm_dp_downstream_debug(struct seq_file *m,
> +			     const u8 dpcd[DP_RECEIVER_CAP_SIZE],
> +			     const u8 port_cap[4],
> +			     const struct edid *edid,
> +			     struct drm_dp_aux *aux);
>  enum drm_mode_subconnector
>  drm_dp_subconnector_type(const u8 dpcd[DP_RECEIVER_CAP_SIZE],
>  			 const u8 port_cap[4]);
-- 
Cheers,
	Lyude Paul (she/her)
	Software Engineer at Red Hat



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