A significant new proposal circulating through Linux kernel mailing lists aims to fundamentally reshape how Linux handles low-power states, bringing the operating system closer to parity with Microsoft Windows' Modern Standby experience. Authored by developer Antheas Kapenekakis, the RFC (Request for Comments) patch series introduces a runtime standby ABI that would allow userspace applications to trigger firmware notifications that make a system appear asleep—with displays off and status LEDs indicating sleep—while the kernel and selected services remain fully active. This architectural shift represents one of the most substantial attempts to date to address Linux's historical limitations in delivering the instant-on, always-connected experience that has become standard on modern mobile devices and increasingly expected on laptops.

The Technical Foundation: Reimagining ACPI _DSM Notifications

At its core, the proposal involves moving several ACPI _DSM (Device Specific Method) firmware notifications out of the traditional suspend sequence and into a reusable transition function that can be invoked while the kernel remains active. According to the technical documentation in the RFC, these notifications—which historically controlled device "appearance" changes during suspend—would become available as a controlled userspace interface at /sys/power/standby. This reorganization allows userland daemons and desktop environments to request presentation state transitions (Screen Off, Sleep Entry/Exit, Turn On Display, etc.) without requiring the kernel to fully suspend.

Searching through official Linux kernel documentation and ACPI specifications reveals that _DSM methods are vendor-defined functions that allow operating systems to interact with platform-specific hardware features. The Kapenekakis series specifically adds support for additional _DSM calls, including the "Turn Display On" call that Microsoft introduced with Windows 22H2, enabling faster wake-up sequences that keep devices logically in low-power presentation states while accelerating user-initiated resume operations.

Why This Matters: The Modern Computing Landscape Demands Change

The driving force behind this proposal emerges most clearly from community discussions on platforms like WindowsForum, where users have long noted the disparity between Windows and Linux power management experiences. As one community member observed, "Modern devices increasingly rely on runtime low-power models that keep DRAM and some subsystems powered so the system can remain connected and resume quickly." This sentiment echoes across numerous forum threads where Linux users on handheld gaming devices and modern laptops express frustration with the traditional suspend/resume model.

Cross-referencing with recent hardware trends confirms this assessment. The handheld gaming ecosystem—including devices like the ASUS ROG Ally, OneXPlayer, and various MSI handhelds—has created new demands that Linux's traditional power management struggles to meet. These devices require predictable "bag safety" with lower standby thermal footprints, background downloads and music playback while screens are off, instant resume for controller-first user experiences, and coordinated firmware presentation changes that match user expectations. The patch notes explicitly mention fixing a ROG Ally controller issue triggered by timing expectations during suspend choreography, highlighting how real-world device problems are driving this architectural evolution.

Community Perspectives: Practical Benefits and Concerns

WindowsForum discussions reveal a community deeply engaged with the practical implications of this proposal. Several users noted that "Linux historically implements suspend semantics differently: s2idle (suspend-to-idle) reaches DRIPS-like power floors, but the kernel's suspend and runtime states and the firmware notifications that modify device presentation were primarily invoked as part of the suspend/resume path." This technical limitation has forced users and distributions to implement workarounds that the new ABI would render unnecessary.

The community identifies several key benefits that align with the technical proposal:

  • Better UX parity with Modern Standby: Linux gains an official, kernel-level mechanism for the "screen off but alive" experience
  • Explicit, documented ABI: Distributions and desktop environments can integrate predictable behavior rather than probing device quirks
  • Granular presentation control: Userspace can select specific presentation states for different use cases
  • Fixes real-world device bugs: The series already resolves timing and quirk issues affecting shipping hardware

However, community members also voice significant concerns that mirror those raised in the technical discussion. One experienced forum participant noted, "No kernel change of this scope is risk-free," highlighting several areas requiring careful attention:

  • Firmware and driver compatibility: Success depends on firmware (_DSM support) and drivers honoring new notification timing
  • Reboot persistence issues: Some _DSM effects persist across reboots, potentially causing devices to boot into sleep presentation
  • Graphics stack interactions: Compositors may not trigger DPMS (Display Power Management Signaling) early enough
  • Security considerations: Keeping networking active while displays are off increases attack surface
  • User expectation management: Without clear UI cues, users might misunderstand power states

Technical Implementation: Mapping to Existing Power Models

Searching through Linux kernel power management documentation reveals how this proposal integrates with existing infrastructure. The series maps presentation states onto an explicit state machine: Active ↔ Screen Off ↔ Sleep ↔ DRIPS (Deepest Runtime Idle Platform State) ↔ Hibernate. The kernel's s2idle path serves as the implementation for runtime idle and corresponds to DRIPS, while the new transition function centralizes callback invocation, making firmware notification sequences available without invoking traditional suspend/resume code paths.

The implementation spans multiple kernel subsystems:

  • ACPI s2idle code: Hosts static callbacks and the transition function
  • Kernel power mainline: Adds the sysfs entry and documents new Standby/Presentation states
  • Platform drivers: Includes adjustments for specific hardware (removing older suspend quirks for ASUS models)
  • Documentation: Comprehensive admin guide updates explaining the new ABI

Industry Context: The Windows Modern Standby Comparison

Microsoft's Modern Standby (formerly Connected Standby) represents the benchmark this Linux proposal aims to approach. According to Microsoft's official documentation and independent analysis, Modern Standby enables systems to remain connected to networks while in low-power states, allowing background tasks like email synchronization, VoIP calls, and software updates to continue. The system achieves this through S0 low-power idle states while presenting the appearance of traditional sleep (S3) to users.

Community discussions on WindowsForum reveal mixed experiences with Modern Standby implementation. While some users praise the instant-on responsiveness and background connectivity, others report issues with battery drain during standby and unexpected wake events. These real-world experiences provide valuable lessons for Linux implementers, particularly regarding the importance of:

  • Clear user interface indicators distinguishing between different power states
  • Comprehensive diagnostic tools (similar to Windows' powercfg /sleepstudy)
  • Granular control over what background activities continue during standby
  • Reliable mechanisms to prevent unwanted wake events

The Handheld Gaming Catalyst

Perhaps the most compelling driver for this change comes from the Linux handheld gaming community. Devices like the Steam Deck have demonstrated that Linux can compete in the consumer gaming space, but power management remains a persistent challenge. Community members report that current solutions often involve "bespoke vendor utilities" and "userland-only workarounds" that vary between devices and distributions.

The RFC explicitly addresses these concerns by providing "a unified, documented ABI that userland can use consistently across vendors." This standardization would benefit not only handheld gaming devices but also traditional laptops seeking to emulate Modern Standby behavior with "fast wake, background activity, and low battery drain when well-implemented."

Security Implications and Mitigation Strategies

Security considerations form a significant part of both the technical proposal and community discussions. Keeping networking active while devices appear asleep creates potential attack vectors that don't exist in traditional suspend states. Community members with security backgrounds emphasize that "Linux distributions will need to make policy choices about background connectivity during runtime standby," suggesting several mitigation strategies:

  • Network filtering policies that restrict background traffic to essential services
  • Enhanced firewall rules during low-power states
  • Clear user notifications when devices enter states with active networking
  • Audit logging of all network activity during standby periods

These security considerations echo lessons learned from Windows Modern Standby implementations, where enterprise deployments often require additional configuration to meet organizational security policies.

Implementation Challenges and Path Forward

The community identifies several implementation challenges that will determine the success of this proposal:

Firmware and Hardware Diversity

Linux's strength in supporting diverse hardware becomes a challenge when implementing standardized power management. The RFC includes "a quirk table for hardware needing timing tweaks," but community members note that "broad device diversity means regressions are possible." Successful implementation will require:

  • Extensive testing across different hardware generations
  • Vendor cooperation for firmware updates where needed
  • Fallback mechanisms for hardware without proper _DSM support
  • Clear documentation of hardware requirements and limitations

Userspace Integration

For the new ABI to deliver value, desktop environments, Wayland compositors, and power managers must integrate support. Community discussions suggest several integration priorities:

  • KDE and GNOME adding runtime standby options to power management settings
  • Wayland compositors coordinating DPMS timing with the new ABI
  • Gamescope and SteamOS optimizing for handheld gaming use cases
  • Distribution policies determining default behaviors and opt-in mechanisms

User Education and Interface Design

Perhaps the most subtle challenge involves managing user expectations. As one community member noted, "Without clear UX cues and predictable defaults, users could misunderstand whether a device is fully asleep (zero draw) or in a runtime standby state (some background activity)." Successful deployment will require:

  • Clear visual indicators distinguishing power states
  • Intuitive settings interfaces explaining trade-offs
  • Comprehensive documentation for both users and administrators
  • Diagnostic tools helping users understand power consumption patterns

Industry Verification and Independent Analysis

Multiple independent sources have verified the technical claims in the proposal. Phoronix's coverage characterizes the work as "more comprehensive than prior Collabora patches" that exposed a /sys/power/lps0_screen_off interface. LWN's analysis reproduces the state diagram and notes the movement of _DSM calls out of suspend sequences, addition of Turn Display On support, and practical effects on devices like the ROG Ally.

Searching through kernel mailing list archives confirms the series spans documentation, s2idle driver changes, power subsystem hooks, and platform driver adjustments. The public nature of these discussions allows for transparent technical review and community feedback—a strength of the open-source development model.

The Road Ahead: Testing, Adoption, and Evolution

The community outlines a realistic timeline for this proposal's evolution:

  1. Kernel review and refinement: The RFC nature means expect follow-ups, quirk additions, and possible API refinements
  2. Vendor firmware updates: Some manufacturers will need BIOS/UEFI updates for proper _DSM implementation
  3. Userspace integration: Desktop environments and power managers adding support over several release cycles
  4. Distribution deployment: Gradual rollout with careful testing and clear user communication

Community recommendations for different stakeholders include:

For kernel developers and vendor engineers:
- Test on representative hardware and log all _DSM call outcomes
- Add explicit transitions to active during reboot paths
- Coordinate with graphics driver maintainers on DPMS timing

For distribution integrators:
- Implement conservative default policies (opt-in rather than opt-out)
- Develop user-facing diagnostics similar to Windows SleepStudy
- Create clear UI distinctions between different power states

For end users:
- Treat early implementations as experimental
- Use hibernate for absolute power-off guarantees during travel
- Provide feedback to help refine the implementation

Conclusion: A Pragmatic Step Toward Modern Power Management

The runtime standby ABI proposal represents a thoughtful, pragmatic approach to addressing one of Linux's most persistent user experience gaps. By focusing on presentation state management rather than attempting to replicate Windows' entire Modern Standby architecture, the proposal offers a path forward that respects Linux's technical foundations while delivering tangible user benefits.

The community's engagement with this proposal—both in technical discussions and practical implementation concerns—demonstrates the collaborative strength of open-source development. While challenges remain around firmware compatibility, security implications, and user education, the foundation being laid could fundamentally improve the Linux experience on modern hardware.

As the proposal moves through the kernel development process, its success will depend not only on technical implementation but also on the broader ecosystem's willingness to adopt and refine these new capabilities. For Windows enthusiasts watching Linux's evolution, this development represents both competition and inspiration—a reminder that user experience improvements often emerge from addressing real-world needs with thoughtful engineering solutions.