drm/i915/dp: Print full branch/sink descriptor

Extend the branch/sink descriptor info with the missing device ID
field. While at it also read out all the descriptor registers in one
transfer and make the debug print more compact.

v2: (Jani)
- Cache the descriptor in intel_dp.
- Split out this change into a separate patch.
v3: (Jani)
- Fix return value check of __intel_dp_read_desc().
- Use %pE instead of %s to print the device ID.

Cc: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Imre Deak <imre.deak@intel.com>
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1477401159-15098-1-git-send-email-imre.deak@intel.com

drivers/gpu/drm/i915/intel_dp.c

@@ -1451,34 +1451,35 @@ static void intel_dp_print_rates(struct intel_dp *intel_dp)
 	DRM_DEBUG_KMS("common rates: %s\n", str);
 }
 
-static void intel_dp_print_hw_revision(struct intel_dp *intel_dp)
+static bool
+__intel_dp_read_desc(struct intel_dp *intel_dp, struct intel_dp_desc *desc)
 {
-	uint8_t rev;
-	int len;
-
-	if (!drm_dp_is_branch(intel_dp->dpcd))
-		return;
+	u32 base = drm_dp_is_branch(intel_dp->dpcd) ? DP_BRANCH_OUI :
+						      DP_SINK_OUI;
 
-	len = drm_dp_dpcd_read(&intel_dp->aux, DP_BRANCH_HW_REV, &rev, 1);
-	if (len < 0)
-		return;
-
-	DRM_DEBUG_KMS("sink hw revision: %d.%d\n", (rev & 0xf0) >> 4, rev & 0xf);
+	return drm_dp_dpcd_read(&intel_dp->aux, base, desc, sizeof(*desc)) ==
+	       sizeof(*desc);
 }
 
-static void intel_dp_print_sw_revision(struct intel_dp *intel_dp)
+static bool intel_dp_read_desc(struct intel_dp *intel_dp)
 {
-	uint8_t rev[2];
-	int len;
+	struct intel_dp_desc *desc = &intel_dp->desc;
+	bool oui_sup = intel_dp->dpcd[DP_DOWN_STREAM_PORT_COUNT] &
+		       DP_OUI_SUPPORT;
+	int dev_id_len;
 
-	if (!drm_dp_is_branch(intel_dp->dpcd))
-		return;
+	if (!__intel_dp_read_desc(intel_dp, desc))
+		return false;
 
-	len = drm_dp_dpcd_read(&intel_dp->aux, DP_BRANCH_SW_REV, &rev, 2);
-	if (len < 0)
-		return;
+	dev_id_len = strnlen(desc->device_id, sizeof(desc->device_id));
+	DRM_DEBUG_KMS("DP %s: OUI %*phD%s dev-ID %*pE HW-rev %d.%d SW-rev %d.%d\n",
+		      drm_dp_is_branch(intel_dp->dpcd) ? "branch" : "sink",
+		      (int)sizeof(desc->oui), desc->oui, oui_sup ? "" : "(NS)",
+		      dev_id_len, desc->device_id,
+		      desc->hw_rev >> 4, desc->hw_rev & 0xf,
+		      desc->sw_major_rev, desc->sw_minor_rev);
 
-	DRM_DEBUG_KMS("sink sw revision: %d.%d\n", rev[0], rev[1]);
+	return true;
 }
 
 static int rate_to_index(int find, const int *rates)
@@ -3621,23 +3622,6 @@ intel_dp_get_dpcd(struct intel_dp *intel_dp)
 	return true;
 }
 
-static void
-intel_dp_probe_oui(struct intel_dp *intel_dp)
-{
-	bool is_branch = drm_dp_is_branch(intel_dp->dpcd);
-	u8 buf[3];
-
-	if (!(intel_dp->dpcd[DP_DOWN_STREAM_PORT_COUNT] & DP_OUI_SUPPORT))
-		return;
-
-	if (drm_dp_dpcd_read(&intel_dp->aux,
-			     is_branch ? DP_BRANCH_OUI : DP_SINK_OUI,
-			     buf, 3) == 3)
-		DRM_DEBUG_KMS("%s OUI: %02hx%02hx%02hx\n",
-			      is_branch ? "Branch" : "Sink",
-			      buf[0], buf[1], buf[2]);
-}
-
 static bool
 intel_dp_can_mst(struct intel_dp *intel_dp)
 {
@@ -4416,10 +4400,7 @@ intel_dp_long_pulse(struct intel_connector *intel_connector)
 
 	intel_dp_print_rates(intel_dp);
 
-	intel_dp_probe_oui(intel_dp);
-
-	intel_dp_print_hw_revision(intel_dp);
-	intel_dp_print_sw_revision(intel_dp);
+	intel_dp_read_desc(intel_dp);
 
 	intel_dp_configure_mst(intel_dp);
 

drivers/gpu/drm/i915/intel_drv.h

@@ -883,6 +883,14 @@ enum link_m_n_set {
 	M2_N2
 };
 
+struct intel_dp_desc {
+	u8 oui[3];
+	u8 device_id[6];
+	u8 hw_rev;
+	u8 sw_major_rev;
+	u8 sw_minor_rev;
+} __packed;
+
 struct intel_dp {
 	i915_reg_t output_reg;
 	i915_reg_t aux_ch_ctl_reg;
@@ -905,6 +913,8 @@ struct intel_dp {
 	/* sink rates as reported by DP_SUPPORTED_LINK_RATES */
 	uint8_t num_sink_rates;
 	int sink_rates[DP_MAX_SUPPORTED_RATES];
+	/* sink or branch descriptor */
+	struct intel_dp_desc desc;
 	struct drm_dp_aux aux;
 	uint8_t train_set[4];
 	int panel_power_up_delay;