Linux 7.3-rc1 Nears 41 Million Lines as AMD GPU Headers Swell the Kernel

Linux 7.3-rc1 is unusually large on paper but broadly conventional in substance. The first candidate in the new kernel cycle expands hardware and graphics support, improves Btrfs and USB4-connected transfers, adds testing-oriented filesystem functionality, and removes obsolete filesystem drivers. Linus Torvalds’s main warning was about the release’s size: a large AMD graphics register-header submission accounts for roughly one-third of the merge-window diff. 14

The 41-million-line milestone needs context

The Linux source tree measured about 40.98 million lines at Linux 7.3-rc1. The reported total includes approximately 5,134,418 blank lines, 4,912,366 comment lines, and 30,937,090 detected lines of code. The AMD GPU kernel driver alone accounts for about 6.5 million lines. 13

That does not mean Linux 7.3 suddenly contains 41 million lines of new functionality. Much of the unusually large change comes from generated AMD GPU register definitions, particularly headers for the DCN 6.0 display engine and other new graphics IP. These files inflate the diffstat without representing an equivalent amount of hand-written, executable driver logic. 14

Torvalds’s assessment was therefore relatively measured: once the AMD register dump is set aside, the statistics look broadly normal for a merge window, with drivers still making up most of the remaining changes. 14

Hardware and driver additions

Linux 7.3 continues preparing the kernel for upcoming platforms while improving support for existing hardware:

• AMD Zen 6: the cycle adds further platform enablement and optimizations for upcoming Zen 6 systems. 2
• Intel Xe3P and Nova Lake: Intel’s next-generation graphics support advances to the point that Nova Lake S graphics are treated as stable and enabled by default, rather than requiring experimental force_probe handling. 250
• AMD graphics: DRM updates include support for newer AMD graphics IP as well as improvements for older Radeon hardware. 50
• Valve’s 2026 Steam Controller: Linux gains kernel driver support for Valve’s upcoming controller hardware. 2
• Apple Silicon: support expands to additional M3-family variants, including initial M3 Ultra, Pro, and Max enablement. 2 A separate report also describes initial USB4 and Thunderbolt support spanning Apple M1 through M3 systems. 3
• Nouveau video decoding: the open-source NVIDIA driver gains NVK Vulkan Video decoding support. 2

For Intel graphics users, the Nova Lake change is particularly notable because it moves support from an explicitly experimental path toward normal driver probing. That status still should not be read as proof that every future graphics feature is complete: DisplayPort 2.1 ALPM, for example, was still being worked on during the Linux 7.3 cycle. 54

Filesystem changes: performance, testing, and cleanup

The filesystem work is varied rather than centered on one major new storage format.

Btrfs performance work

Btrfs receives performance-oriented changes in the 7.3 merge window. The available release summary identifies this as one of the cycle’s notable filesystem improvements, although it does not establish a single headline benchmark or universal performance gain. 2

FailFS for error-path testing

Linux 7.3 adds FailFS, a deliberately failing pseudo-filesystem. Unlike a normal filesystem, operations reaching FailFS return EOPNOTSUPP, the error code for an unsupported operation. Its purpose is to help developers test how software handles filesystem failures; it complements the earlier NULLFS testing filesystem. 35

WOF-compressed NTFS files

NTFS gains read support for files compressed using Windows Overlay Filter mechanisms, commonly referred to as WOF-compressed files. This improves the kernel’s ability to access that class of Windows-created compressed data from Linux. 2

Removal of obsolete drivers

The cycle removes the obsolete EFS and FreeVxFS filesystem drivers. Removing unmaintained legacy code reduces what the kernel has to carry and maintain, but the change is primarily a cleanup item rather than a new end-user feature. 2

USB-C validation and lower-latency USB4STREAM transfers

Linux 7.3’s USB-C code begins checking whether cables actually support the alternate modes they are being asked to carry. The checks include cable identity information, limitations of passive USB 2.0 cables, and the expected plug information for active cables. The goal is to avoid treating an unsuitable cable as if it could support DisplayPort or other alternate-mode operation. 3637

The cycle also adds a busy-poll option to USB4STREAM, Intel’s protocol for transferring raw data between USB4- or Thunderbolt-connected systems. Busy polling can reduce latency by avoiding some interrupt and worker-scheduling delays, but it increases CPU activity, so it is aimed at latency-sensitive use cases rather than being a universal default. 3945

When will Linux 7.3 be released?

Linux 7.3-rc1 was tagged on August 30, 2026, after the two-week merge window. 343 It is a test release, not the finished Linux 7.3 kernel.

The cycle is expected to run through roughly six or seven release candidates. Based on that schedule, the stable release is projected for mid-to-late October 2026, but the date can move if regressions require additional testing or another release candidate. 34

The practical takeaway

Linux 7.3-rc1’s headline is its scale, not a single disruptive kernel feature. The near-41-million-line count is real, but the AMD DCN 6.0 register-header contribution makes the merge look larger than the amount of new runtime logic alone would suggest. For users, the more tangible changes are broader support for upcoming AMD and Intel platforms, new Valve and Apple hardware enablement, improved graphics coverage, better filesystem testing and compatibility, and more flexible low-latency transfers over USB4.