[PATCH v3 02/12] drm/i915: Clear the repeater bit on HDCP disable

[Sean Paul]

From: Sean Paul <seanpaul at chromium.org>

On HDCP disable, clear the repeater bit. This ensures if we connect a
non-repeater sink after a repeater, the bit is in the state we expect.

Fixes: ee5e5e7a5e0f (drm/i915: Add HDCP framework + base implementation)
Cc: Chris Wilson <chris at chris-wilson.co.uk>
Cc: Ramalingam C <ramalingam.c at intel.com>
Cc: Daniel Vetter <daniel.vetter at ffwll.ch>
Cc: Sean Paul <seanpaul at chromium.org>
Cc: Jani Nikula <jani.nikula at linux.intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen at linux.intel.com>
Cc: Rodrigo Vivi <rodrigo.vivi at intel.com>
Cc: intel-gfx at lists.freedesktop.org
Cc: <stable at vger.kernel.org> # v4.17+
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/20191212190230.188505-3-sean@poorly.run #v2

Changes in v2:
-Added to the set
Changes in v3:
-None
  I had previously agreed that clearing the rep_ctl bits on enable would
  also be a good idea. However when I committed that idea to code, it
  didn't look right. So let's rely on enables and disables being paired
  and everything outside of that will be considered a bug
---
 drivers/gpu/drm/i915/display/intel_hdcp.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/drivers/gpu/drm/i915/display/intel_hdcp.c b/drivers/gpu/drm/i915/display/intel_hdcp.c
index eaab9008feef..c4394c8e10eb 100644
--- a/drivers/gpu/drm/i915/display/intel_hdcp.c
+++ b/drivers/gpu/drm/i915/display/intel_hdcp.c
@@ -773,6 +773,7 @@ static int _intel_hdcp_disable(struct intel_connector *connector)
 	struct intel_digital_port *intel_dig_port = conn_to_dig_port(connector);
 	enum port port = intel_dig_port->base.port;
 	enum transcoder cpu_transcoder = hdcp->cpu_transcoder;
+	u32 repeater_ctl;
 	int ret;
 
 	DRM_DEBUG_KMS("[%s:%d] HDCP is being disabled...\n",
@@ -787,6 +788,10 @@ static int _intel_hdcp_disable(struct intel_connector *connector)
 		return -ETIMEDOUT;
 	}
 
+	repeater_ctl = intel_hdcp_get_repeater_ctl(dev_priv, cpu_transcoder,
+						   port);
+	I915_WRITE(HDCP_REP_CTL, I915_READ(HDCP_REP_CTL) & ~repeater_ctl);
+
 	ret = hdcp->shim->toggle_signalling(intel_dig_port, false);
 	if (ret) {
 		DRM_ERROR("Failed to disable HDCP signalling\n");
-- 
Sean Paul, Software Engineer, Google / Chromium OS