# Linux 7.4 improves hibernation power management for PCIe bridges

> **Key takeaway:** PCIe bridges can now be powered down during hibernation, aligning the process with suspend behavior to help meet energy certifications.

**Published:** 2026-10-23T12:44:01+00:00 
**Source:** Phoronix Benchmarks & Drivers 
**Category:** kernel-os 
**Canonical URL:** https://fosswire.org/news/linux-74-improves-hibernation-power-management-for-pcie-brid.html 

## Summary
Improvements to the PCI/PCIe subsystem have been merged into the Linux 7.4 merge window. The update ensures that PCIe bridges with downstream devices are transitioned to low-power states during hibernation, a step previously missing from the hibernate poweroff flow.

## Aligning hibernation with suspend behavior
- During **S3 suspend**, `pci_pm_suspend_noirq()` puts PCIe bridges with downstream devices into **D3hot** or **D3cold** states.
- Previously, the **hibernate poweroff_noirq** path only called `pci_prepare_to_sleep()` for devices without subordinates.
- This meant bridges with active children remained in **D0** during hibernation.
- The fix allows bridges to power down during **S4** hibernation, assisting hardware designs (especially those with **dGPUs**) in meeting energy certification criteria.

## Why it matters
This change helps hardware manufacturers meet global energy efficiency standards for devices running Linux, particularly in systems with discrete GPUs.