[Intel-gfx] [PATCH] drm/i915/ddi: Check for unexpectedly disabled transcoders

[Imre Deak]

The DDI eDP/pipe A/B/C transcoders must be enabled whenever we observe
the DDI buffer of the port connected to them to be enabled (via
DDI_BUF_CTL). Add a consistency check for this to the HW readout code of
these transcoders.

Signed-off-by: Imre Deak <imre.deak at intel.com>
---
 drivers/gpu/drm/i915/intel_ddi.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/gpu/drm/i915/intel_ddi.c b/drivers/gpu/drm/i915/intel_ddi.c
index ad11540ac436..0476d1d33bfb 100644
--- a/drivers/gpu/drm/i915/intel_ddi.c
+++ b/drivers/gpu/drm/i915/intel_ddi.c
@@ -2029,6 +2029,8 @@ static void intel_ddi_get_encoder_pipes(struct intel_encoder *encoder,
 	if (port == PORT_A) {
 		tmp = I915_READ(TRANS_DDI_FUNC_CTL(TRANSCODER_EDP));
 
+		WARN_ON(!(tmp & TRANS_DDI_FUNC_ENABLE));
+
 		switch (tmp & TRANS_DDI_EDP_INPUT_MASK) {
 		default:
 			MISSING_CASE(tmp & TRANS_DDI_EDP_INPUT_MASK);
@@ -2057,6 +2059,8 @@ static void intel_ddi_get_encoder_pipes(struct intel_encoder *encoder,
 		if ((tmp & TRANS_DDI_PORT_MASK) != TRANS_DDI_SELECT_PORT(port))
 			continue;
 
+		WARN_ON(!(tmp & TRANS_DDI_FUNC_ENABLE));
+
 		if ((tmp & TRANS_DDI_MODE_SELECT_MASK) ==
 		    TRANS_DDI_MODE_SELECT_DP_MST)
 			mst_pipe_mask |= BIT(p);
-- 
2.13.2