Speaker
Description
With the rapid proliferation of high-quality digital media, effective content protection mechanisms have become essential to prevent unauthorized copying, redistribution, and piracy. This presentation explores the architecture and implementation of content protection (CP) technologies in the Linux graphics stack, focusing primarily on High-bandwidth Digital Content Protection (HDCP) and Protected Audio Video Path (PAVP).
We begin by examining the motivations behind content protection: protecting creators’ intellectual property and meeting stringent compliance requirements imposed by content providers and licensing authorities. The talk outlines the historical limitations of HDCP 1.x—its reliance on aging cryptographic algorithms such as RC4, limited interface support, and vulnerability to reverse engineering—and describes how HDCP 2.x addresses these shortcomings through modern encryption (RSA, AES), enhanced revocation mechanisms, and expanded compatibility with newer interfaces like HDMI 2.0, DisplayPort, and USB Type-C.
The presentation then details how content protection flows from userspace to the kernel driver. We cover how userspace software negotiates and sets content protection properties (CONTENT_PROTECTION and CONTENT_TYPE) via DRM/KMS APIs, and how kernel drivers enforce these policies, maintain state transitions, and ensure authenticated link establishment between the GPU and display sink. Special emphasis is placed on how HDCP is typically used only for external displays, while PAVP provides hardware-protected sessions internally and can be sufficient for trusted embedded panels.
Attendees will gain insight into the specific driver responsibilities—such as signaling userspace when protection states change—and the integration of HDCP and PAVP to achieve a secure end-to-end content pipeline. The session will also discuss the practical challenges and trade-offs associated with implementing CP, including usability, latency, power consumption, and the complexity of supporting multiple evolving standards in an open-source environment.
The presentation aims to provide developers, driver maintainers, and architects with a clear understanding of the current state of content protection on Linux, the reasons behind specific design choices, and the practical considerations when enabling CP in production systems.
| Code of Conduct | Yes |
|---|---|
| GSoC, EVoC or Outreachy | No |
| In-person or virtual presentation | Virtual |
