drm/i915/dp: Suspend/resume DP tunnels

Suspend and resume DP tunnels during system suspend/resume, disabling
the BW allocation mode during suspend, re-enabling it after resume. This
reflects the link's BW management component (Thunderbolt CM) disabling
BWA during suspend. Before any BW requests the driver must read the
sink's DPRX capabilities (since the BW manager requires this
information, so snoops for it on AUX), so ensure this read takes place.

Reviewed-by: Uma Shankar <uma.shankar@intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Imre Deak <imre.deak@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240220211841.448846-20-imre.deak@intel.com

diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c
index 51b24cab51fff7b706a3036ea1080cbd7c1789c7..0b9c33a000f95fe67edb731c33ade1dd175fa915 100644 (file)
--- a/drivers/gpu/drm/i915/display/intel_dp.c
+++ b/drivers/gpu/drm/i915/display/intel_dp.c
@@ -36,6 +36,7 @@
 #include <asm/byteorder.h>
 
 #include <drm/display/drm_dp_helper.h>
+#include <drm/display/drm_dp_tunnel.h>
 #include <drm/display/drm_dsc_helper.h>
 #include <drm/display/drm_hdmi_helper.h>
 #include <drm/drm_atomic_helper.h>
@@ -3313,18 +3314,21 @@ void intel_dp_sync_state(struct intel_encoder *encoder,
                         const struct intel_crtc_state *crtc_state)
 {
        struct intel_dp *intel_dp = enc_to_intel_dp(encoder);
-
-       if (!crtc_state)
-               return;
+       bool dpcd_updated = false;
 
        /*
         * Don't clobber DPCD if it's been already read out during output
         * setup (eDP) or detect.
         */
-       if (intel_dp->dpcd[DP_DPCD_REV] == 0)
+       if (crtc_state && intel_dp->dpcd[DP_DPCD_REV] == 0) {
                intel_dp_get_dpcd(intel_dp);
+               dpcd_updated = true;
+       }
 
-       intel_dp_reset_max_link_params(intel_dp);
+       intel_dp_tunnel_resume(intel_dp, crtc_state, dpcd_updated);
+
+       if (crtc_state)
+               intel_dp_reset_max_link_params(intel_dp);
 }
 
 bool intel_dp_initial_fastset_check(struct intel_encoder *encoder,
@@ -5950,6 +5954,8 @@ void intel_dp_encoder_suspend(struct intel_encoder *intel_encoder)
        struct intel_dp *intel_dp = enc_to_intel_dp(intel_encoder);
 
        intel_pps_vdd_off_sync(intel_dp);
+
+       intel_dp_tunnel_suspend(intel_dp);
 }
 
 void intel_dp_encoder_shutdown(struct intel_encoder *intel_encoder)