[PATCH 03/13] drm/i915: WARN if HDCP signalling is enabled upon disable

[Sean Paul]

From: Sean Paul <seanpaul at chromium.org>

HDCP signalling should not be left on, WARN if it is

Cc: Ville Syrjälä <ville.syrjala at linux.intel.com>
Cc: Daniel Vetter <daniel.vetter at ffwll.ch>
Reviewed-by: Ramalingam C <ramalingam.c at intel.com>
Signed-off-by: Sean Paul <seanpaul at chromium.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20191212190230.188505-4-sean@poorly.run #v2

Changes in v2:
- Added to the set in lieu of just clearing the bit
---
 drivers/gpu/drm/i915/display/intel_ddi.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/gpu/drm/i915/display/intel_ddi.c b/drivers/gpu/drm/i915/display/intel_ddi.c
index 5b6f32517c75..4a5bdf3ef51d 100644
--- a/drivers/gpu/drm/i915/display/intel_ddi.c
+++ b/drivers/gpu/drm/i915/display/intel_ddi.c
@@ -1951,6 +1951,8 @@ void intel_ddi_disable_transcoder_func(const struct intel_crtc_state *crtc_state
 	i915_reg_t reg = TRANS_DDI_FUNC_CTL(cpu_transcoder);
 	u32 val = I915_READ(reg);
 
+	WARN_ON(val & TRANS_DDI_HDCP_SIGNALLING);
+
 	if (INTEL_GEN(dev_priv) >= 12) {
 		val &= ~(TRANS_DDI_FUNC_ENABLE | TGL_TRANS_DDI_PORT_MASK |
 			 TRANS_DDI_DP_VC_PAYLOAD_ALLOC);
-- 
Sean Paul, Software Engineer, Google / Chromium OS