drm/dp: Pimp drm_dp_downstream_max_bpc()

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

v2: Use Returns: for kdoc (Lyude)

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200904115354.25336-8-ville.syrjala@linux.intel.com
Reviewed-by: Lyude Paul <lyude@redhat.com>
Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>

diff --git a/drivers/gpu/drm/drm_dp_helper.c b/drivers/gpu/drm/drm_dp_helper.c
index 56a3ba1477133ab8bd2491f8fbbd2d940b333c53..e1af400df65cf7f16c07b9a78414d4cbb4f0908d 100644 (file)
--- 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
+ * drm_dp_downstream_max_bpc() - extract downstream facing port max
  *                               bits per component
  * @dpcd: DisplayPort configuration data
- * @port_cap: port capabilities
- *
- * See also:
- * drm_dp_read_downstream_info()
- * drm_dp_downstream_max_clock()
+ * @port_cap: downstream facing port capabilities
+ * @edid: EDID
  *
  * Returns: Max bpc on success or 0 if max bpc not defined
  */
 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 53a0a3d9a22df937bcd278dcb821319f9efff965..0bf31f9a8af56b1d3640a1839d1da59d30cd8a20 100644 (file)
--- 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 5ecff6824a30951c098107e1adad92baf4bc3e6f..027307f17823e74ee2ee32e9ccfebb95ae9d0755 100644 (file)
--- 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 4f946826dfce3bd131d875e0e6d286b0c09614d7..6218de1294c147f24f149490345e477f07dcb363 100644 (file)
--- 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]);