drm/i915/mst: Use MST sideband message transactions for dpms control

Use the POWER_DOWN_PHY and POWER_UP_PHY sideband message transactions to
set power states for downstream sinks. Apart from giving us the ability
to set power state for individual sinks, this fixes the below test for
me.

$ xrandr --display :0 --output DP-2-2-8 --off
$ xrandr --display :0 --output DP-2-2-1 --off
$ xrandr --display :0 --output DP-2-2-8 --auto #Black screen
$ xrandr --display :0 --output DP-2-2-1 --auto

v2: Modify and document the dpms and port disable order (Ville)
    Add comment explaining is_mst = !crtc_state equivalence(Ville, Maarten)

v3 by Jani: rebase

References: https://bugs.freedesktop.org/show_bug.cgi?id=90963
References: https://bugs.freedesktop.org/show_bug.cgi?id=88124
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Lyude <lyude@redhat.com>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Reviewed-by: Lyude Paul <lyude@redhat.com>
Acked-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Signed-off-by: Dhinakaran Pandiyan <dhinakaran.pandiyan@intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20171003142211.860-1-jani.nikula@intel.com

diff --git a/drivers/gpu/drm/i915/intel_ddi.c b/drivers/gpu/drm/i915/intel_ddi.c
index 65f4b678679164992517e1d86609706369e743dd..511aa60e01765f231c815cb12556585bf5c2aa6c 100644 (file)
--- a/drivers/gpu/drm/i915/intel_ddi.c
+++ b/drivers/gpu/drm/i915/intel_ddi.c
@@ -2162,7 +2162,8 @@ static void intel_ddi_pre_enable_dp(struct intel_encoder *encoder,
                intel_prepare_dp_ddi_buffers(encoder);
 
        intel_ddi_init_dp_buf_reg(encoder);
-       intel_dp_sink_dpms(intel_dp, DRM_MODE_DPMS_ON);
+       if (!link_mst)
+               intel_dp_sink_dpms(intel_dp, DRM_MODE_DPMS_ON);
        intel_dp_start_link_train(intel_dp);
        if (port != PORT_A || INTEL_GEN(dev_priv) >= 9)
                intel_dp_stop_link_train(intel_dp);
@@ -2236,12 +2237,21 @@ static void intel_ddi_post_disable(struct intel_encoder *intel_encoder,
        uint32_t val;
        bool wait = false;
 
-       /* old_crtc_state and old_conn_state are NULL when called from DP_MST */
-
        if (type == INTEL_OUTPUT_DP || type == INTEL_OUTPUT_EDP) {
+               /*
+                * old_crtc_state and old_conn_state are NULL when called from
+                * DP_MST. The main connector associated with this port is never
+                * bound to a crtc for MST.
+                */
+               bool is_mst = !old_crtc_state;
                struct intel_dp *intel_dp = enc_to_intel_dp(encoder);
 
-               intel_dp_sink_dpms(intel_dp, DRM_MODE_DPMS_OFF);
+               /*
+                * Power down sink before disabling the port, otherwise we end
+                * up getting interrupts from the sink on detecting link loss.
+                */
+               if (!is_mst)
+                       intel_dp_sink_dpms(intel_dp, DRM_MODE_DPMS_OFF);
        }
 
        val = I915_READ(DDI_BUF_CTL(port));

diff --git a/drivers/gpu/drm/i915/intel_dp_mst.c b/drivers/gpu/drm/i915/intel_dp_mst.c
index 9a396f483f8beeb468c7ccbd3d0b8edf962b0b9c..3c131e2544cfae81e41f80caca54db478d3bf944 100644 (file)
--- a/drivers/gpu/drm/i915/intel_dp_mst.c
+++ b/drivers/gpu/drm/i915/intel_dp_mst.c
@@ -162,14 +162,19 @@ static void intel_mst_post_disable_dp(struct intel_encoder *encoder,
 
        drm_dp_mst_deallocate_vcpi(&intel_dp->mst_mgr, connector->port);
 
+       /*
+        * Power down mst path before disabling the port, otherwise we end
+        * up getting interrupts from the sink upon detecting link loss.
+        */
+       drm_dp_send_power_updown_phy(&intel_dp->mst_mgr, connector->port,
+                                    false);
+
        intel_dp->active_mst_links--;
 
        intel_mst->connector = NULL;
        if (intel_dp->active_mst_links == 0) {
                intel_dig_port->base.post_disable(&intel_dig_port->base,
                                                  NULL, NULL);
-
-               intel_dp_sink_dpms(intel_dp, DRM_MODE_DPMS_OFF);
        }
        DRM_DEBUG_KMS("active links %d\n", intel_dp->active_mst_links);
 }
@@ -196,6 +201,7 @@ static void intel_mst_pre_enable_dp(struct intel_encoder *encoder,
 
        DRM_DEBUG_KMS("active links %d\n", intel_dp->active_mst_links);
 
+       drm_dp_send_power_updown_phy(&intel_dp->mst_mgr, connector->port, true);
        if (intel_dp->active_mst_links == 0)
                intel_dig_port->base.pre_enable(&intel_dig_port->base,
                                                pipe_config, NULL);