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From: Sean Paul <sean@poorly.run>
To: dri-devel@lists.freedesktop.org, intel-gfx@lists.freedesktop.org
Cc: seanpaul@chromium.org, rodrigo.vivi@intel.com
Subject: [PATCH] drm/i915/hdcp: Avoid duplicate HDCP enables
Date: Wed, 20 May 2020 15:47:44 -0400	[thread overview]
Message-ID: <20200520194744.48936-1-sean@poorly.run> (raw)

From: Sean Paul <seanpaul@chromium.org>

If userspace sets the CP property to DESIRED while it's already ENABLED,
the driver will try to re-enable HDCP. On some displays, this will
result in R0' mismatches. I'm guessing this is because the display is
still sending back Ri instead of re-authenticating.

At any rate, we can fix this inefficiency easily enough by just nooping
the DESIRED property set if HDCP is already ENABLED.

Signed-off-by: Sean Paul <seanpaul@chromium.org>
---

I suspect this is the actual root cause I was chasing with
"drm/i915/hdcp: Add additional R0' wait". I was able to reproduce the
R0` messages by marking HDCP desired while it was already enabled. This
_should_ work, but it seems like some displays handle it more graciously
than others.


 drivers/gpu/drm/i915/display/intel_hdcp.c | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/i915/display/intel_hdcp.c b/drivers/gpu/drm/i915/display/intel_hdcp.c
index 2cbc4619b4ce..f770fe0c5595 100644
--- a/drivers/gpu/drm/i915/display/intel_hdcp.c
+++ b/drivers/gpu/drm/i915/display/intel_hdcp.c
@@ -2156,12 +2156,16 @@ void intel_hdcp_atomic_check(struct drm_connector *connector,
 	}
 
 	/*
-	 * Nothing to do if the state didn't change, or HDCP was activated since
-	 * the last commit. And also no change in hdcp content type.
+	 * Nothing to do if content type is unchanged and one of:
+	 *  - state didn't change
+	 *  - HDCP was activated since the last commit
+	 *  - attempting to set to desired while already enabled
 	 */
 	if (old_cp == new_cp ||
 	    (old_cp == DRM_MODE_CONTENT_PROTECTION_DESIRED &&
-	     new_cp == DRM_MODE_CONTENT_PROTECTION_ENABLED)) {
+	     new_cp == DRM_MODE_CONTENT_PROTECTION_ENABLED) ||
+	    (old_cp == DRM_MODE_CONTENT_PROTECTION_ENABLED &&
+	     new_cp == DRM_MODE_CONTENT_PROTECTION_DESIRED)) {
 		if (old_state->hdcp_content_type ==
 				new_state->hdcp_content_type)
 			return;
-- 
Sean Paul, Software Engineer, Google / Chromium OS

_______________________________________________
dri-devel mailing list
dri-devel@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/dri-devel

WARNING: multiple messages have this Message-ID (diff)
From: Sean Paul <sean@poorly.run>
To: dri-devel@lists.freedesktop.org, intel-gfx@lists.freedesktop.org
Cc: seanpaul@chromium.org
Subject: [Intel-gfx] [PATCH] drm/i915/hdcp: Avoid duplicate HDCP enables
Date: Wed, 20 May 2020 15:47:44 -0400	[thread overview]
Message-ID: <20200520194744.48936-1-sean@poorly.run> (raw)

From: Sean Paul <seanpaul@chromium.org>

If userspace sets the CP property to DESIRED while it's already ENABLED,
the driver will try to re-enable HDCP. On some displays, this will
result in R0' mismatches. I'm guessing this is because the display is
still sending back Ri instead of re-authenticating.

At any rate, we can fix this inefficiency easily enough by just nooping
the DESIRED property set if HDCP is already ENABLED.

Signed-off-by: Sean Paul <seanpaul@chromium.org>
---

I suspect this is the actual root cause I was chasing with
"drm/i915/hdcp: Add additional R0' wait". I was able to reproduce the
R0` messages by marking HDCP desired while it was already enabled. This
_should_ work, but it seems like some displays handle it more graciously
than others.


 drivers/gpu/drm/i915/display/intel_hdcp.c | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/i915/display/intel_hdcp.c b/drivers/gpu/drm/i915/display/intel_hdcp.c
index 2cbc4619b4ce..f770fe0c5595 100644
--- a/drivers/gpu/drm/i915/display/intel_hdcp.c
+++ b/drivers/gpu/drm/i915/display/intel_hdcp.c
@@ -2156,12 +2156,16 @@ void intel_hdcp_atomic_check(struct drm_connector *connector,
 	}
 
 	/*
-	 * Nothing to do if the state didn't change, or HDCP was activated since
-	 * the last commit. And also no change in hdcp content type.
+	 * Nothing to do if content type is unchanged and one of:
+	 *  - state didn't change
+	 *  - HDCP was activated since the last commit
+	 *  - attempting to set to desired while already enabled
 	 */
 	if (old_cp == new_cp ||
 	    (old_cp == DRM_MODE_CONTENT_PROTECTION_DESIRED &&
-	     new_cp == DRM_MODE_CONTENT_PROTECTION_ENABLED)) {
+	     new_cp == DRM_MODE_CONTENT_PROTECTION_ENABLED) ||
+	    (old_cp == DRM_MODE_CONTENT_PROTECTION_ENABLED &&
+	     new_cp == DRM_MODE_CONTENT_PROTECTION_DESIRED)) {
 		if (old_state->hdcp_content_type ==
 				new_state->hdcp_content_type)
 			return;
-- 
Sean Paul, Software Engineer, Google / Chromium OS

_______________________________________________
Intel-gfx mailing list
Intel-gfx@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/intel-gfx

             reply	other threads:[~2020-05-20 19:47 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-05-20 19:47 Sean Paul [this message]
2020-05-20 19:47 ` [Intel-gfx] [PATCH] drm/i915/hdcp: Avoid duplicate HDCP enables Sean Paul
2020-05-20 20:23 ` [Intel-gfx] ✓ Fi.CI.BAT: success for " Patchwork
2020-05-21  4:57 ` [PATCH] " Ramalingam C
2020-05-21  4:57   ` [Intel-gfx] " Ramalingam C
2020-05-21  9:27   ` Anshuman Gupta
2020-05-21  9:27     ` [Intel-gfx] " Anshuman Gupta
2020-05-21 13:38     ` Sean Paul
2020-05-21 13:38       ` [Intel-gfx] " Sean Paul
2020-05-21  5:21 ` [Intel-gfx] ✗ Fi.CI.BUILD: failure for drm/i915/hdcp: Avoid duplicate HDCP enables (rev2) Patchwork

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