drm/i915: Reject unusable power sequencers

On ICP-ADP the pins used by the second PPS can be alternatively
muxed to some other function. In that case the second power
sequencer is unusable.

Unfortunately (on my ADL Thinkpad T14 gen3 at least) the
BIOS still likes to enable the VDD on the second PPS (due
to the VBT declaring the second bogus eDP panel) even when
not correctly muxed, so we need to deal with it somehow.
For now let's just initialize the PPS as normal, and then
use the normal eDP probe failure VDD off path to turn it off
(and release the wakeref the PPS init grabbed). The
alternative of just declaring that the platform has a single
PPS doesn't really work since it would cause the second eDP
probe to also try to use the first PPS and thus clobber the
state for the first (real) eDP panel.

Cc: Animesh Manna <animesh.manna@intel.com>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20221125173156.31689-7-ville.syrjala@linux.intel.com
Reviewed-by: Animesh Manna <animesh.manna@intel.com>

diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c
index 06844f45df4150c73c891ed93728069aa9a78a80..72cf83a274058a13c78e239962763549312f8bf9 100644 (file)
--- a/drivers/gpu/drm/i915/display/intel_dp.c
+++ b/drivers/gpu/drm/i915/display/intel_dp.c
@@ -5224,7 +5224,17 @@ static bool intel_edp_init_connector(struct intel_dp *intel_dp,
        intel_bios_init_panel_early(dev_priv, &intel_connector->panel,
                                    encoder->devdata);
 
-       intel_pps_init(intel_dp);
+       if (!intel_pps_init(intel_dp)) {
+               drm_info(&dev_priv->drm,
+                        "[ENCODER:%d:%s] unusable PPS, disabling eDP\n",
+                        encoder->base.base.id, encoder->base.name);
+               /*
+                * The BIOS may have still enabled VDD on the PPS even
+                * though it's unusable. Make sure we turn it back off
+                * and to release the power domain references/etc.
+                */
+               goto out_vdd_off;
+       }
 
        /* Cache DPCD and EDID for edp. */
        has_dpcd = intel_edp_init_dpcd(intel_dp);

diff --git a/drivers/gpu/drm/i915/display/intel_pps.c b/drivers/gpu/drm/i915/display/intel_pps.c
index 77b0a4f27abc9bfa00d79dd91e2d21133147bdd9..d18c1c58dfcfed397ea7d030aa5b8e6d1ce72a90 100644 (file)
--- a/drivers/gpu/drm/i915/display/intel_pps.c
+++ b/drivers/gpu/drm/i915/display/intel_pps.c
@@ -327,6 +327,18 @@ static int intel_num_pps(struct drm_i915_private *i915)
        return 1;
 }
 
+static bool intel_pps_is_valid(struct intel_dp *intel_dp)
+{
+       struct drm_i915_private *i915 = dp_to_i915(intel_dp);
+
+       if (intel_dp->pps.pps_idx == 1 &&
+           INTEL_PCH_TYPE(i915) >= PCH_ICP &&
+           INTEL_PCH_TYPE(i915) < PCH_MTP)
+               return intel_de_read(i915, SOUTH_CHICKEN1) & ICP_SECOND_PPS_IO_SELECT;
+
+       return true;
+}
+
 static int
 bxt_initial_pps_idx(struct drm_i915_private *i915, pps_check check)
 {
@@ -340,7 +352,7 @@ bxt_initial_pps_idx(struct drm_i915_private *i915, pps_check check)
        return -1;
 }
 
-static void
+static bool
 pps_initial_setup(struct intel_dp *intel_dp)
 {
        struct intel_encoder *encoder = &dp_to_dig_port(intel_dp)->base;
@@ -351,7 +363,7 @@ pps_initial_setup(struct intel_dp *intel_dp)
 
        if (IS_VALLEYVIEW(i915) || IS_CHERRYVIEW(i915)) {
                vlv_initial_power_sequencer_setup(intel_dp);
-               return;
+               return true;
        }
 
        /* first ask the VBT */
@@ -377,13 +389,14 @@ pps_initial_setup(struct intel_dp *intel_dp)
                            "[ENCODER:%d:%s] no initial power sequencer, assuming %d\n",
                            encoder->base.base.id, encoder->base.name,
                            intel_dp->pps.pps_idx);
-               return;
+       } else {
+               drm_dbg_kms(&i915->drm,
+                           "[ENCODER:%d:%s] initial power sequencer: %d\n",
+                           encoder->base.base.id, encoder->base.name,
+                           intel_dp->pps.pps_idx);
        }
 
-       drm_dbg_kms(&i915->drm,
-                   "[ENCODER:%d:%s] initial power sequencer: %d\n",
-                   encoder->base.base.id, encoder->base.name,
-                   intel_dp->pps.pps_idx);
+       return intel_pps_is_valid(intel_dp);
 }
 
 void intel_pps_reset_all(struct drm_i915_private *dev_priv)
@@ -1504,9 +1517,10 @@ void intel_pps_encoder_reset(struct intel_dp *intel_dp)
        }
 }
 
-void intel_pps_init(struct intel_dp *intel_dp)
+bool intel_pps_init(struct intel_dp *intel_dp)
 {
        intel_wakeref_t wakeref;
+       bool ret;
 
        intel_dp->pps.initializing = true;
        INIT_DELAYED_WORK(&intel_dp->pps.panel_vdd_work, edp_panel_vdd_work);
@@ -1514,12 +1528,14 @@ void intel_pps_init(struct intel_dp *intel_dp)
        pps_init_timestamps(intel_dp);
 
        with_intel_pps_lock(intel_dp, wakeref) {
-               pps_initial_setup(intel_dp);
+               ret = pps_initial_setup(intel_dp);
 
                pps_init_delays(intel_dp);
                pps_init_registers(intel_dp, false);
                pps_vdd_init(intel_dp);
        }
+
+       return ret;
 }
 
 static void pps_init_late(struct intel_dp *intel_dp)

diff --git a/drivers/gpu/drm/i915/display/intel_pps.h b/drivers/gpu/drm/i915/display/intel_pps.h
index a3a56f903f26db5b6cf55d2ed339ed72eb7c78c8..a2c2467e3c224966341a730abeac7844bbcbfbcb 100644 (file)
--- a/drivers/gpu/drm/i915/display/intel_pps.h
+++ b/drivers/gpu/drm/i915/display/intel_pps.h
@@ -40,7 +40,7 @@ void intel_pps_vdd_off_sync(struct intel_dp *intel_dp);
 bool intel_pps_have_panel_power_or_vdd(struct intel_dp *intel_dp);
 void intel_pps_wait_power_cycle(struct intel_dp *intel_dp);
 
-void intel_pps_init(struct intel_dp *intel_dp);
+bool intel_pps_init(struct intel_dp *intel_dp);
 void intel_pps_init_late(struct intel_dp *intel_dp);
 void intel_pps_encoder_reset(struct intel_dp *intel_dp);
 void intel_pps_reset_all(struct drm_i915_private *i915);

diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
index 0fa86da12af1cd80433def4dfd5d046b931f27b5..168ef34d110b9c4f33275b0b7322dc064ee583c9 100644 (file)
--- a/drivers/gpu/drm/i915/i915_reg.h
+++ b/drivers/gpu/drm/i915/i915_reg.h
@@ -6241,6 +6241,7 @@
 #define  CHASSIS_CLK_REQ_DURATION_MASK (0xf << 8)
 #define  CHASSIS_CLK_REQ_DURATION(x)   ((x) << 8)
 #define  SBCLK_RUN_REFCLK_DIS          (1 << 7)
+#define  ICP_SECOND_PPS_IO_SELECT      REG_BIT(2)
 #define  SPT_PWM_GRANULARITY           (1 << 0)
 #define SOUTH_CHICKEN2         _MMIO(0xc2004)
 #define  FDI_MPHY_IOSFSB_RESET_STATUS  (1 << 13)