| aDSP | Audio digital signal processor |
| ALSA | Advanced Linux Sound Architecture |
| APSS | Applications processor subsystem |
| ASMP | Asymmetric multiprocessing |
| BSP | Board Support Package. The collection of kernel configuration, device trees, drivers, and firmware needed to run Linux on a specific hardware platform. |
| cDSP | Compute digital signal processor |
| CFS | Completely Fair Scheduler. The default Linux process scheduler that distributes CPU time proportionally among runnable tasks. |
| CID | Context identifier |
| CMA | Contiguous Memory Allocator. A kernel mechanism that reserves a contiguous physical memory region for devices that require physically contiguous DMA buffers. |
| COFF | Common object file format |
| crosvm | The ChromeOS virtual machine monitor |
| DDR | Double data rate |
| DMA | Direct memory access |
| DMA-buf | DMA Buffer. A kernel framework for sharing memory buffers between multiple devices and subsystems (for example, GPU, camera, DSP) without unnecessary copies. |
| DMIPS | Dhrystone million instructions per second |
| DSI | Display Serial Interface |
| DTB | Device Tree Blob. The compiled binary form of a Device Tree Source file, passed to the kernel at boot to describe the hardware topology of the platform. |
| DTBO | DTB overlays |
| DTS | Device Tree Source. The human-readable source file (.dts) that describes the hardware components and their relationships on a board. |
| DTSI | Device Tree Source Include. A shared Device Tree fragment (.dtsi) that describes SoC-level hardware and is included by board-level DTS files. |
| DTSO | Device tree source overlay |
| DVFS | Dynamic Voltage and Frequency Scaling. A power management technique that adjusts CPU, L3 cache, and DDR operating points at runtime to balance performance and power consumption. |
| EAS | Energy Aware Scheduling. A Linux scheduler extension that uses the CPU energy model and PELT signals to place tasks on the most energy-efficient CPU core during wake-up. |
| eDP | Embedded DisplayPort |
| EFI | Extensible firmware interface |
| EL2 | Exception Level 2. The ARM exception level at which a hypervisor (such as KVM) runs. Device trees with an el2 suffix are built for configurations where Linux operates as a KVM host. |
| ELF | Executable and linking format |
| EM | Energy model |
| ESP | EFI System Partition. A FAT32 partition that holds the boot manager, kernel image, initramfs, and optionally the DTB on Qualcomm Linux platforms. |
| FAT | File allocation table |
| GCC | GNU compiler collection |
| GIC | Generic interrupt controller |
| GPIO | General Purpose Input/Output. A configurable digital pin on an SoC that can be used for input sensing or output signaling, managed by the pinctrl subsystem. |
| HDMI | High-Definition Multimedia Interface |
| HYP | Hypervisor |
| I2C | Interintegrated circuit |
| Initrd | Initial RAM disk |
| IPC | Interprocess communication |
| IRQ | Interrupt request |
| ISR | Interrupt service routine |
| kas | A build tool for the Yocto Project that manages layer checkouts and build configurations through declarative YAML files. Qualcomm Linux uses kas configurations stored in meta-qcom/ci/. |
| KGDB | Kernel GNU Debugger. A kernel built-in debugger that allows source-level debugging of the Linux kernel over a serial connection using GDB on the host. |
| KGSL | Kernel graphics support layer |
| KVM | Kernel-based Virtual Machine. The Linux hypervisor that enables running guest virtual machines on Qualcomm platforms when the host kernel operates at EL2. |
| L3 | Level 3 cache |
| LLCC | Last level cache controller |
| LPASS | Low-power audio subsystem |
| LTS | Long-Term Support. A kernel release maintained with security and stability patches for an extended period. Qualcomm Linux tracks an LTS kernel (currently v6.18.x). |
| MPSS | Modem peripheral subsystem software |
| MTP | Mobile test platform |
| OS | Operating system |
| PAS | Peripheral authentication service |
| PBL | Primary Boot Loader. The first-stage firmware executed from ROM on Qualcomm platforms after power-on. It initialises minimal hardware and loads XBL. |
| PCI | Peripheral component interconnect |
| PD | Protection domain |
| PE | Portable executable file format |
| PELT | Per Entity Load Tracking. A kernel mechanism that tracks the historical CPU utilisation of individual tasks and control groups, used by EAS and other scheduler features. |
| PIL | Peripheral image loader |
| PSCI | Power state coordination interface |
| PWM | Pulse width modulation |
| QCAP | Qualcomm crash analysis portal |
| QEMU | Quick emulator |
| QPST | Qualcomm Product Support Tool |
| QXDM | Qualcomm extensible diagnostic monitor |
| remoteproc | Remote Processor. The Linux kernel framework for loading firmware into and managing heterogeneous processors (aDSP, cDSP, modem) present on Qualcomm SoCs. |
| RPE | Reset, power, error |
| RT | Real-Time. A kernel configuration (PREEMPT_RT) that reduces scheduling latency to bounded, deterministic values, suitable for time-critical workloads. |
| RTOS | Real-time operating system |
| SLPI | Sensor low-power island |
| SMD | Shared memory driver |
| SMP2P | Shared memory point to point |
| SoC | System on Chip. An integrated circuit that combines CPU cores, memory controllers, DSPs, and peripheral interfaces on a single die. Examples: QCS6490, QCS9100, QCS8300. |
| SPI | Serial peripheral interface |
| SSR | Subsystem restart |
| SVM | Secondary virtual machine |
| TLMM | Top-level mode multiplexer |
| TTY | Teletype |
| UCLAMP | Utilization clamping |
| UEFI | Unified Extensible Firmware Interface. The firmware standard used on Qualcomm Linux platforms. UEFI loads systemd-boot as the boot manager after XBL completes platform initialisation. |
| UKI | Unified Kernel Image. A single EFI binary that bundles the kernel, initramfs, and optionally the DTB, built with systemd-ukify and stored on the ESP. |
| URI | Uniform resource identifier |
| VFIO | Virtual function I/O |
| VHE | Virtual host extensions |
| VM | Virtual machine |
| VMM | Virtual machine monitor |
| WCNSS | Wireless connect subsystem |
| WDOG | Watchdog service |
| WLAN | Wireless local area network |
| WPSS | Wireless processor subsystem |
| XBL | eXtensible Boot Loader. The second-stage boot loader on Qualcomm platforms. XBL performs DDR initialisation and loads the UEFI firmware image. |
