drm/i915/dp: cache eDP DPCD data

Cache the first 4 bytes of DPCD data in the eDP case.  It's unlikely to
change and can save us some trouble at link training time.

Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>

diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 6d49a9f..84e33ae 100644 (file)
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -350,6 +350,7 @@ typedef struct drm_i915_private {
                int bpp;
                struct edp_power_seq pps;
        } edp;
+       bool no_aux_handshake;
 
        struct notifier_block lid_notifier;
 

diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
index 944dfe1..7fa8282 100644 (file)
--- a/drivers/gpu/drm/i915/intel_dp.c
+++ b/drivers/gpu/drm/i915/intel_dp.c
@@ -1724,6 +1724,26 @@ intel_dp_init(struct drm_device *dev, int output_reg)
 
        intel_dp_i2c_init(intel_dp, intel_connector, name);
 
+       /* Cache some DPCD data in the eDP case */
+       if (is_edp(intel_dp)) {
+               int ret;
+               bool was_on;
+
+               was_on = ironlake_edp_panel_on(intel_dp);
+               ret = intel_dp_aux_native_read(intel_dp, DP_DPCD_REV,
+                                              intel_dp->dpcd,
+                                              sizeof(intel_dp->dpcd));
+               if (ret == sizeof(intel_dp->dpcd)) {
+                       if (intel_dp->dpcd[0] >= 0x11)
+                               dev_priv->no_aux_handshake = intel_dp->dpcd[3] &
+                                       DP_NO_AUX_HANDSHAKE_LINK_TRAINING;
+               } else {
+                       DRM_ERROR("failed to retrieve link info\n");
+               }
+               if (!was_on)
+                       ironlake_edp_panel_off(dev);
+       }
+
        intel_encoder->hot_plug = intel_dp_hot_plug;
 
        if (is_edp(intel_dp)) {