[Intel-gfx] [PATCH 09/24] drm/i915: detect PCH encoders on Haswell

[Eugeni Dodonov]

On Haswell, the recommended PCH-connected output is the one driven by DDI
E in FDI mode, used for VGA connection. All the others are handled by the
CPU.

Note that this does not accounts for Haswell/PPT combination yet.

Signed-off-by: Eugeni Dodonov <eugeni.dodonov at intel.com>
---
 drivers/gpu/drm/i915/intel_display.c |   12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index 758173d..ea1ac15 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -2631,6 +2631,18 @@ static bool intel_crtc_driving_pch(struct drm_crtc *crtc)
 		if (encoder->base.crtc != crtc)
 			continue;
 
+		/* On Haswell, LPT PCH handles the VGA connection via FDI, and Haswell
+		 * CPU handles all others */
+		if (IS_HASWELL(dev)) {
+			if (HAS_PCH_LPT(dev) && (encoder->type == DRM_MODE_ENCODER_DAC))
+				return true;
+			else {
+				DRM_DEBUG_KMS("Haswell detected encoder %d, assuming is CPU\n",
+						encoder->type);
+				return false;
+			}
+		}
+
 		switch (encoder->type) {
 		case INTEL_OUTPUT_EDP:
 			if (!intel_encoder_is_pch_edp(&encoder->base))
-- 
1.7.10