drm/i915/gvt: add mmio init for virtual display

GVT implements a purely virtual monitor for virtual GPU independent of
the host. Some DDI related MMIO are not initialized in current code
which cause the display initialization failure in guest. This patch
fills the gap.

Signed-off-by: Pei Zhang <pei.zhang@intel.com>
Signed-off-by: Zhenyu Wang <zhenyuw@linux.intel.com>
diff --git a/drivers/gpu/drm/i915/gvt/display.c b/drivers/gpu/drm/i915/gvt/display.c
index 4cf2b29..e0261fc 100644
--- a/drivers/gpu/drm/i915/gvt/display.c
+++ b/drivers/gpu/drm/i915/gvt/display.c
@@ -189,17 +189,44 @@ static void emulate_monitor_status_change(struct intel_vgpu *vgpu)
 	}
 
 	if (intel_vgpu_has_monitor_on_port(vgpu, PORT_B)) {
-		vgpu_vreg(vgpu, SDEISR) |= SDE_PORTB_HOTPLUG_CPT;
 		vgpu_vreg(vgpu, SFUSE_STRAP) |= SFUSE_STRAP_DDIB_DETECTED;
+		vgpu_vreg(vgpu, TRANS_DDI_FUNC_CTL(TRANSCODER_A)) &=
+			~(TRANS_DDI_BPC_MASK | TRANS_DDI_MODE_SELECT_MASK |
+			TRANS_DDI_PORT_MASK);
+		vgpu_vreg(vgpu, TRANS_DDI_FUNC_CTL(TRANSCODER_A)) |=
+			(TRANS_DDI_BPC_8 | TRANS_DDI_MODE_SELECT_DP_SST |
+			(PORT_B << TRANS_DDI_PORT_SHIFT) |
+			TRANS_DDI_FUNC_ENABLE);
+		vgpu_vreg(vgpu, DDI_BUF_CTL(PORT_B)) |= DDI_BUF_CTL_ENABLE;
+		vgpu_vreg(vgpu, DDI_BUF_CTL(PORT_B)) &= ~DDI_BUF_IS_IDLE;
+		vgpu_vreg(vgpu, SDEISR) |= SDE_PORTB_HOTPLUG_CPT;
 	}
 
 	if (intel_vgpu_has_monitor_on_port(vgpu, PORT_C)) {
 		vgpu_vreg(vgpu, SDEISR) |= SDE_PORTC_HOTPLUG_CPT;
+		vgpu_vreg(vgpu, TRANS_DDI_FUNC_CTL(TRANSCODER_A)) &=
+			~(TRANS_DDI_BPC_MASK | TRANS_DDI_MODE_SELECT_MASK |
+			TRANS_DDI_PORT_MASK);
+		vgpu_vreg(vgpu, TRANS_DDI_FUNC_CTL(TRANSCODER_A)) |=
+			(TRANS_DDI_BPC_8 | TRANS_DDI_MODE_SELECT_DP_SST |
+			(PORT_C << TRANS_DDI_PORT_SHIFT) |
+			TRANS_DDI_FUNC_ENABLE);
+		vgpu_vreg(vgpu, DDI_BUF_CTL(PORT_C)) |= DDI_BUF_CTL_ENABLE;
+		vgpu_vreg(vgpu, DDI_BUF_CTL(PORT_C)) &= ~DDI_BUF_IS_IDLE;
 		vgpu_vreg(vgpu, SFUSE_STRAP) |= SFUSE_STRAP_DDIC_DETECTED;
 	}
 
 	if (intel_vgpu_has_monitor_on_port(vgpu, PORT_D)) {
 		vgpu_vreg(vgpu, SDEISR) |= SDE_PORTD_HOTPLUG_CPT;
+		vgpu_vreg(vgpu, TRANS_DDI_FUNC_CTL(TRANSCODER_A)) &=
+			~(TRANS_DDI_BPC_MASK | TRANS_DDI_MODE_SELECT_MASK |
+			TRANS_DDI_PORT_MASK);
+		vgpu_vreg(vgpu, TRANS_DDI_FUNC_CTL(TRANSCODER_A)) |=
+			(TRANS_DDI_BPC_8 | TRANS_DDI_MODE_SELECT_DP_SST |
+			(PORT_D << TRANS_DDI_PORT_SHIFT) |
+			TRANS_DDI_FUNC_ENABLE);
+		vgpu_vreg(vgpu, DDI_BUF_CTL(PORT_D)) |= DDI_BUF_CTL_ENABLE;
+		vgpu_vreg(vgpu, DDI_BUF_CTL(PORT_D)) &= ~DDI_BUF_IS_IDLE;
 		vgpu_vreg(vgpu, SFUSE_STRAP) |= SFUSE_STRAP_DDID_DETECTED;
 	}