[PATCH v4 03/14] 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
Link: https://patchwork.freedesktop.org/patch/msgid/20200117193103.156821-4-sean@poorly.run #v3

Changes in v2:
-Added to the set in lieu of just clearing the bit
Changes in v3:
-None
Changes in v4:
-None
---
 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 a1fd8fd67c855..fc84cd7c724fb 100644
--- a/drivers/gpu/drm/i915/display/intel_ddi.c
+++ b/drivers/gpu/drm/i915/display/intel_ddi.c
@@ -2013,6 +2013,8 @@ void intel_ddi_disable_transcoder_func(const struct intel_crtc_state *crtc_state
 	val = intel_de_read(dev_priv, TRANS_DDI_FUNC_CTL(cpu_transcoder));
 	val &= ~TRANS_DDI_FUNC_ENABLE;
 
+	WARN_ON(val & TRANS_DDI_HDCP_SIGNALLING);
+
 	if (INTEL_GEN(dev_priv) >= 12) {
 		if (!intel_dp_mst_is_master_trans(crtc_state)) {
 			val &= ~(TGL_TRANS_DDI_PORT_MASK |
-- 
Sean Paul, Software Engineer, Google / Chromium OS