[Intel-gfx] [PATCH v2 03/13] drm/hdcp: Update property value on content type and user changes

Sean Paul
2021-09-15T20:39:05Z

From: Sean Paul <seanpaul@chromium.org>

This patch updates the connector's property value in 2 cases which were
previously missed:

1- Content type changes. The value should revert back to DESIRED from
ENABLED in case the driver must re-authenticate the link due to the
new content type.

2- Userspace sets value to DESIRED while ENABLED. In this case, the
value should be reset immediately to ENABLED since the link is
actively being encrypted.

To accommodate these changes, I've split up the conditionals to make
things a bit more clear (as much as one can with this mess of state).

Signed-off-by: Sean Paul <seanpaul@chromium.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20210913175747.47456-4-sean@poorly.run #v1

Changes in v2:
-None
---
drivers/gpu/drm/drm_hdcp.c | 26 +++++++++++++++++---------
1 file changed, 17 insertions(+), 9 deletions(-)

diff --git a/drivers/gpu/drm/drm_hdcp.c b/drivers/gpu/drm/drm_hdcp.c
index dd8fa91c51d6..742313ce8f6f 100644
--- a/drivers/gpu/drm/drm_hdcp.c
+++ b/drivers/gpu/drm/drm_hdcp.c
@@ -487,21 +487,29 @@ bool drm_hdcp_atomic_check(struct drm_connector *connector,
return true;

/*
- * Nothing to do if content type is unchanged and one of:
- * - state didn't change
+ * Content type changes require an HDCP disable/enable cycle.
+ */
+ if (new_conn_state->hdcp_content_type != old_conn_state->hdcp_content_type) {
+ new_conn_state->content_protection =
+ DRM_MODE_CONTENT_PROTECTION_DESIRED;
+ return true;
+ }
+
+ /*
+ * Ignore meaningless state changes:
* - HDCP was activated since the last commit
- * - attempting to set to desired while already enabled
+ * - Attempting to set to desired while already enabled
*/
- if (old_hdcp == new_hdcp ||
- (old_hdcp == DRM_MODE_CONTENT_PROTECTION_DESIRED &&
+ if ((old_hdcp == DRM_MODE_CONTENT_PROTECTION_DESIRED &&
new_hdcp == DRM_MODE_CONTENT_PROTECTION_ENABLED) ||
(old_hdcp == DRM_MODE_CONTENT_PROTECTION_ENABLED &&
new_hdcp == DRM_MODE_CONTENT_PROTECTION_DESIRED)) {
- if (old_conn_state->hdcp_content_type ==
- new_conn_state->hdcp_content_type)
- return false;
+ new_conn_state->content_protection =
+ DRM_MODE_CONTENT_PROTECTION_ENABLED;
+ return false;
}

- return true;
+ /* Finally, if state changes, we need action */
+ return old_hdcp != new_hdcp;
}
EXPORT_SYMBOL(drm_hdcp_atomic_check);
--
Sean Paul, Software Engineer, Google / Chromium OS