drm/i915: Don't switch to TPS1 when disabling DP_TP_CTL

AFAICS Bspec has never asked us to switch to TPS1 when *disabling*
DP_TP_CTL. Let's stop doing that in case it confuses something.
We do have to switch before we *enable* DP_TP_CTL, but that
is already being handled correctly.

v2: Do the same for FDI
v3: Rebase

Reviewed-by: Imre Deak <imre.deak@intel.com> #v1
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230308212627.7601-1-ville.syrjala@linux.intel.com

drivers/gpu/drm/i915/display/intel_ddi.c

@@ -2618,8 +2618,7 @@ static void intel_disable_ddi_buf(struct intel_encoder *encoder,
 
 	if (intel_crtc_has_dp_encoder(crtc_state))
 		intel_de_rmw(dev_priv, dp_tp_ctl_reg(encoder, crtc_state),
-			     DP_TP_CTL_ENABLE | DP_TP_CTL_LINK_TRAIN_MASK,
-			     DP_TP_CTL_LINK_TRAIN_PAT1);
+			     DP_TP_CTL_ENABLE, 0);
 
 	/* Disable FEC in DP Sink */
 	intel_ddi_disable_fec_state(encoder, crtc_state);
@@ -3140,8 +3139,7 @@ static void intel_ddi_prepare_link_retrain(struct intel_dp *intel_dp,
 			wait = true;
 		}
 
-		dp_tp_ctl &= ~(DP_TP_CTL_ENABLE | DP_TP_CTL_LINK_TRAIN_MASK);
-		dp_tp_ctl |= DP_TP_CTL_LINK_TRAIN_PAT1;
+		dp_tp_ctl &= ~DP_TP_CTL_ENABLE;
 		intel_de_write(dev_priv, dp_tp_ctl_reg(encoder, crtc_state), dp_tp_ctl);
 		intel_de_posting_read(dev_priv, dp_tp_ctl_reg(encoder, crtc_state));
 

drivers/gpu/drm/i915/display/intel_fdi.c

@@ -845,9 +845,7 @@ void hsw_fdi_link_train(struct intel_encoder *encoder,
 		intel_de_posting_read(dev_priv, DDI_BUF_CTL(PORT_E));
 
 		/* Disable DP_TP_CTL and FDI_RX_CTL and retry */
-		intel_de_rmw(dev_priv, DP_TP_CTL(PORT_E),
-			     DP_TP_CTL_ENABLE | DP_TP_CTL_LINK_TRAIN_MASK,
-			     DP_TP_CTL_LINK_TRAIN_PAT1);
+		intel_de_rmw(dev_priv, DP_TP_CTL(PORT_E), DP_TP_CTL_ENABLE, 0);
 		intel_de_posting_read(dev_priv, DP_TP_CTL(PORT_E));
 
 		intel_wait_ddi_buf_idle(dev_priv, PORT_E);