drm/i915/dsc: fix DSC power domains for DSI

Fix several issues with DSC power domains that did not take DSI
transcoders into account:

- On TGL+ we need to use PW2 for DSC on pipe A, not transcoder A. There
  is no longer an eDP transcoder, but there are two DSI transcoders
  which may be connected to pipe A.

- On TGL+ we need to use the pipe, not transcoder, power domains for DSC
  on pipes other than A. Again, there are DSI transcoders.

- On ICL we need to use PW2 for DSC also for DSI transcoders, not just
  for the eDP transcoder.

Using is_pipe_dsc() also adds the warning about ICL pipe A DSC, which
does not exist.

Cc: José Roberto de Souza <jose.souza@intel.com>
Cc: Manasi Navare <manasi.d.navare@intel.com>
Cc: Vandita Kulkarni <vandita.kulkarni@intel.com>
Reviewed-by: Vandita Kulkarni <vandita.kulkarni@intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191212134728.18432-1-jani.nikula@intel.com

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

@@ -469,25 +469,27 @@ int intel_dsc_compute_params(struct intel_encoder *encoder,
 enum intel_display_power_domain
 intel_dsc_power_domain(const struct intel_crtc_state *crtc_state)
 {
-	struct drm_i915_private *i915 = to_i915(crtc_state->uapi.crtc->dev);
-	enum transcoder cpu_transcoder = crtc_state->cpu_transcoder;
+	struct intel_crtc *crtc = to_intel_crtc(crtc_state->uapi.crtc);
+	struct drm_i915_private *i915 = to_i915(crtc->base.dev);
+	enum pipe pipe = crtc->pipe;
 
 	/*
-	 * On ICL VDSC/joining for eDP transcoder uses a separate power well,
-	 * PW2. This requires POWER_DOMAIN_TRANSCODER_VDSC_PW2 power domain.
-	 * For any other transcoder, VDSC/joining uses the power well associated
-	 * with the pipe/transcoder in use. Hence another reference on the
-	 * transcoder power domain will suffice.
+	 * VDSC/joining uses a separate power well, PW2, and requires
+	 * POWER_DOMAIN_TRANSCODER_VDSC_PW2 power domain in two cases:
 	 *
-	 * On TGL we have the same mapping, but for transcoder A (the special
-	 * TRANSCODER_EDP is gone).
+	 *  - ICL eDP/DSI transcoder
+	 *  - TGL pipe A
+	 *
+	 * For any other pipe, VDSC/joining uses the power well associated with
+	 * the pipe in use. Hence another reference on the pipe power domain
+	 * will suffice. (Except no VDSC/joining on ICL pipe A.)
 	 */
-	if (INTEL_GEN(i915) >= 12 && cpu_transcoder == TRANSCODER_A)
-		return POWER_DOMAIN_TRANSCODER_VDSC_PW2;
-	else if (cpu_transcoder == TRANSCODER_EDP)
+	if (INTEL_GEN(i915) >= 12 && pipe == PIPE_A)
 		return POWER_DOMAIN_TRANSCODER_VDSC_PW2;
+	else if (is_pipe_dsc(crtc_state))
+		return POWER_DOMAIN_PIPE(pipe);
 	else
-		return POWER_DOMAIN_TRANSCODER(cpu_transcoder);
+		return POWER_DOMAIN_TRANSCODER_VDSC_PW2;
 }
 
 static void intel_dsc_pps_configure(struct intel_encoder *encoder,