PreSonus Quantum Linux

Discovery, research, desktop audio integration, and experimental releases for PreSonus Quantum Thunderbolt interfaces. Nicholas Johnson's upstream RFC driver, snd-quantum, is now the main driver and default build backend. The earlier in-house snd-quantum2626 driver remains an explicit research and recovery fallback.

"Upstream RFC" means a proposal submitted for Linux kernel review; it does not mean the driver has been merged into mainline Linux. This independent project is not affiliated with PreSonus or Fender.

Install with APT | Download DEB/RPM packages | All releases

Recommended for Ubuntu, Debian, Pop!_OS, and Linux Mint on x86_64. Install quantum-dkms through our signed repository; no Git clone or manual driver build is needed. DKMS builds the module for your kernel and handles future kernel updates when matching headers are installed. Only the Quantum 2626 Thunderbolt interface is currently enabled; the driver remains experimental.

Ubuntu 22.04/24.04 and Debian 12/13 are tested package bases. See the compatibility table for Mint/Pop, desktop audio, and custom-kernel limits. Already installed an older driver? Back up custom audio settings and read the migration notes first.

With curl and gpg installed, download the repository configuration and public key:

APT_URL=https://jamie-steele.github.io/presonus-quantum-linux
curl -fsSLo quantum-archive-keyring.gpg "$APT_URL/quantum-archive-keyring.gpg"
curl -fsSLo quantum.sources "$APT_URL/quantum.sources"
gpg --show-keys --with-fingerprint quantum-archive-keyring.gpg
cat quantum.sources

Stop if the key fingerprint does not match:

5F83 9BAB 8E48 F657 2044 A442 D98A C6B0 3628 D7BE

The public key expires on 2027-09-27. Check that quantum.sources points to the APT URL above and uses Signed-By: /etc/apt/keyrings/quantum-archive-keyring.gpg, then install both files:

sudo install -d -m 0755 /etc/apt/keyrings
sudo install -m 0644 quantum-archive-keyring.gpg /etc/apt/keyrings/
sudo install -m 0644 quantum.sources /etc/apt/sources.list.d/quantum.sources

sudo apt update
sudo apt install --no-install-recommends --no-remove linux-headers-$(uname -r) quantum-dkms

Review the proposed package changes before accepting. Reboot when convenient, then check:

lspci -nnk -d 1c67:0104

The driver-in-use line should report snd-quantum. Secure Boot may require your distro's DKMS key enrollment. Installation does not restart audio services; test playback and inputs after reboot. Future published versions arrive through normal sudo apt update / sudo apt upgrade.

Prefer a standalone package? These are the 20260820.rfc1.s1148921-2 release assets. APT above automatically selects newer published versions as they arrive.

Verify the downloaded package against revision-2 checksums, then follow the native package installation commands. Installing a downloaded DEB alone does not subscribe to APT updates. Arch users can follow the source/DKMS installation guide.

Downloads are attached to GitHub Releases, not the sidebar's Packages registry. GitHub Packages' supported formats do not include APT/DEB or RPM; our signed APT repository is hosted on GitHub Pages.

• Nicholas Johnson authored the original RFC patch and its cover letter.
• EMATech/quantum is an unofficial contributor collaboration repository, with an editable, out-of-tree adaptation of the RFC. It is not the official RFC or its publication channel. Its commits do not trigger our releases; we monitor the official linux-sound submission through Patchwork/lore.
• This repository retains protocol discovery, hardware findings, test tools, distro release integration, and ALSA UCM/WirePlumber profiles. Future UCM contributions belong in alsa-ucm-conf, with separate validation and submission.
• Contributing explains RFC review replies, kernel patch submission, collaboration-tree changes, and ALSA profile contributions.

Only Quantum 2626 (1c67:0104, Thunderbolt 3 / PCIe) is currently enabled and hardware-tested. Quantum, Quantum 2, and Quantum 4848 remain research targets; USB Quantum ES/HD devices use a different transport and are not supported by this PCI driver.

The desktop profile is fixed at 48 kHz, 26-channel S32_LE, exposing 13 stereo outputs and 26 mono inputs. Physical analog playback/capture and bounded duplex tests have succeeded with the in-house driver. The RFC has separate, mixed hardware evidence: a successful cold-boot listening interval, but also DMA/IOMMU faults and command timeouts during rate changes and desktop discovery.

The RFC implements MIDI, mixer/clock controls, and removal handling; these are not established hardware acceptance results here. Its original PCM code exposes 26 channels at all advertised rates. The in-house backend's separate 26/18/8 channel constraints must not be attributed to the RFC. Higher rates, physical S/PDIF/ADAT routing, sustained stability, and cross-distro hardware behavior need further testing. See current evidence.

The release page is the distribution point for experimental RFC snapshots. The release workflow checks the ALSA Patchwork feed every six hours and publishes each complete new Nicholas Johnson Quantum RFC only after the distro build matrix passes. An RFC remains an experimental prerelease even when compilation succeeds.

Releases contain the original driver source, DKMS build support, UCM profiles, WirePlumber 0.4/0.5 configuration, provenance, checksums, and distro build logs. Debian, Ubuntu, Fedora, openSUSE Tumbleweed, and Arch are the x86_64 CI targets; derivatives and other kernels require their own validation. There is no universal precompiled .ko: DKMS builds for the installed kernel and rebuilds on upgrades.

Start with APT installation or the DEB/RPM downloads above. The full release guide covers distro dependencies, migration, package removal, signing, and release operation. Source builds below are for development and research; they are not required for package users.

Install matching kernel headers, a compiler, Make, Git, and curl, then run:

make -C driver upstream-sync
make -C driver W=1

driver/upstream.lock pins the original RFC by URL and hashes. The explicit sync downloads into an external cache; ordinary builds are offline. Automated releases carry their own RFC manifest and do not silently change this reviewed source pin. For the in-house fallback, use make -C driver QUANTUM_DRIVER=inhouse W=1.

Choose the backend explicitly when installing:

sudo make -C driver install-upstream
# Fallback: sudo make -C driver install-inhouse

Installation writes the chosen module, desktop configuration, and a modprobe policy blacklisting the alternate backend, then refreshes initramfs using update-initramfs, dracut, or mkinitcpio. It does not load/unload modules or restart audio services. The selected driver takes effect on a later boot. Existing explicit module-load rules can override blacklist-based autoload policy; verify the actual binding after reboot. Secure Boot needs a trusted module signature.

Older findings remain available as research history. Use the current status and testing guide before acting on old commands. This cleanup does not grant new hardware acceptance or authorize register sweeps.

Repository-authored material retains its existing license. RFC release bundles preserve Nicholas Johnson's authorship, source SPDX notices, and GPL-2.0 text; the root MIT license does not relicense the upstream driver.