drm/i915/skl: Read sink supported rates from edp panel

v2: Using DP_SUPPORTED_LINK_RATES macro for supported_rates array (Satheesh).
v3: Reading dpcd's supported link rates tables based upon edp version in the
same patch.
v4: Move version check under is_edp (Satheesh)
v5: Using le16 for rates, some naming, and removing nested if block (Ville)
v6: Correctly using DP_MAX_SUPPORTED_RATES and removing DP_SUPPORTED_LINK_RATES
(Ville)
v7: Incorrectly removed DP_SUPPORTED_LINK_RATES in v6, re-adding it
v8: Checking return value of intel_dp_dpcd_read_wake() (Ville)

Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Sonika Jindal <sonika.jindal@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
index 0a57763..18d4a7c 100644 (file)
--- a/drivers/gpu/drm/i915/intel_dp.c
+++ b/drivers/gpu/drm/i915/intel_dp.c
@@ -1117,6 +1117,33 @@ hsw_dp_set_ddi_pll_sel(struct intel_crtc_state *pipe_config, int link_bw)
        }
 }
 
+static int
+intel_read_sink_rates(struct intel_dp *intel_dp, uint32_t *sink_rates)
+{
+       struct drm_device *dev = intel_dp_to_dev(intel_dp);
+       int i = 0;
+       uint16_t val;
+
+       if (INTEL_INFO(dev)->gen >= 9 && intel_dp->supported_rates[0]) {
+               /*
+                * Receiver supports only main-link rate selection by
+                * link rate table method, so read link rates from
+                * supported_link_rates
+                */
+               for (i = 0; i < DP_MAX_SUPPORTED_RATES; ++i) {
+                       val = le16_to_cpu(intel_dp->supported_rates[i]);
+                       if (val == 0)
+                               break;
+
+                       sink_rates[i] = val * 200;
+               }
+
+               if (i <= 0)
+                       DRM_ERROR("No rates in SUPPORTED_LINK_RATES");
+       }
+       return i;
+}
+
 static void
 intel_dp_set_clock(struct intel_encoder *encoder,
                   struct intel_crtc_state *pipe_config, int link_bw)
@@ -3578,6 +3605,7 @@ intel_dp_get_dpcd(struct intel_dp *intel_dp)
        struct intel_digital_port *dig_port = dp_to_dig_port(intel_dp);
        struct drm_device *dev = dig_port->base.base.dev;
        struct drm_i915_private *dev_priv = dev->dev_private;
+       uint8_t rev;
 
        if (intel_dp_dpcd_read_wake(&intel_dp->aux, 0x000, intel_dp->dpcd,
                                    sizeof(intel_dp->dpcd)) < 0)
@@ -3609,6 +3637,16 @@ intel_dp_get_dpcd(struct intel_dp *intel_dp)
        } else
                intel_dp->use_tps3 = false;
 
+       /* Intermediate frequency support */
+       if (is_edp(intel_dp) &&
+           (intel_dp->dpcd[DP_EDP_CONFIGURATION_CAP] & DP_DPCD_DISPLAY_CONTROL_CAPABLE) &&
+           (intel_dp_dpcd_read_wake(&intel_dp->aux, DP_EDP_DPCD_REV, &rev, 1) == 1) &&
+           (rev >= 0x03)) { /* eDp v1.4 or higher */
+               intel_dp_dpcd_read_wake(&intel_dp->aux,
+                               DP_SUPPORTED_LINK_RATES,
+                               intel_dp->supported_rates,
+                               sizeof(intel_dp->supported_rates));
+       }
        if (!(intel_dp->dpcd[DP_DOWNSTREAMPORT_PRESENT] &
              DP_DWN_STRM_PORT_PRESENT))
                return true; /* native DP sink */

diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
index fbf8149..e05d153 100644 (file)
--- a/drivers/gpu/drm/i915/intel_drv.h
+++ b/drivers/gpu/drm/i915/intel_drv.h
@@ -626,6 +626,7 @@ struct intel_dp {
        uint8_t dpcd[DP_RECEIVER_CAP_SIZE];
        uint8_t psr_dpcd[EDP_PSR_RECEIVER_CAP_SIZE];
        uint8_t downstream_ports[DP_MAX_DOWNSTREAM_PORTS];
+       __le16 supported_rates[DP_MAX_SUPPORTED_RATES];
        struct drm_dp_aux aux;
        uint8_t train_set[4];
        int panel_power_up_delay;