drm/i915: set TRANSCODER_EDP even earlier

Instead of setting it at the beginning of haswell_crtc_mode_set, let's
set it at the beginning of intel_crtc_mode_set. When
intel_crt_mode_set calls drm_vblank_pre_modeset we already need to
have the transcoder_edp correctly set, because eventually
drm_vblank_pre_modeset calls functions that call i915_pipe_enabled
from i915_irq.c, which will read PIPECONF(cpu_transcoder).

This is a bug that affects us since we added support for
TRANSCODER_EDP, but I was only able to see the problem after
suspending a machine with the power well disabled (got an "unclaimed
register" error.
Signed-off-by: NPaulo Zanoni <paulo.r.zanoni@intel.com>
Reviewed-by: NJani Nikula <jani.nikula@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/intel_display.c

@@ -5633,11 +5633,6 @@ static int haswell_crtc_mode_set(struct drm_crtc *crtc,
 		num_connectors++;
 	}
 
-	if (is_cpu_edp)
-		intel_crtc->cpu_transcoder = TRANSCODER_EDP;
-	else
-		intel_crtc->cpu_transcoder = pipe;
-
 	/* We are not sure yet this won't happen. */
 	WARN(!HAS_PCH_LPT(dev), "Unexpected PCH type %d\n",
 	     INTEL_PCH_TYPE(dev));
@@ -5702,6 +5697,11 @@ static int intel_crtc_mode_set(struct drm_crtc *crtc,
 	int pipe = intel_crtc->pipe;
 	int ret;
 
+	if (IS_HASWELL(dev) && intel_pipe_has_type(crtc, INTEL_OUTPUT_EDP))
+		intel_crtc->cpu_transcoder = TRANSCODER_EDP;
+	else
+		intel_crtc->cpu_transcoder = pipe;
+
 	drm_vblank_pre_modeset(dev, pipe);
 
 	ret = dev_priv->display.crtc_mode_set(crtc, mode, adjusted_mode,