intel_gtt

As intel_gtt is not a direct command-line executable, there is no conventional syntax to invoke it. Its functionality is embedded within the Linux kernel's i915 graphics driver. Configuration or inspection of GTT-related behavior is typically achieved through interaction with the kernel module or the debugfs filesystem, rather than executing a standalone intel_gtt command.

modprobe i915 [module_option=value]

cat /sys/kernel/debug/dri/0/i915_gtt_info

i915.enable_psr
    Controls Panel Self Refresh for power saving, affecting display memory traffic handled by GTT. This is an i915 kernel module option.

i915.enable_dc
    Enables Display Coherence for power saving, influencing how display planes are managed in memory. This is an i915 kernel module option.

i915.enable_fbc
    Controls Frame Buffer Compression, a memory bandwidth optimization that relies on GTT for efficient data access. This is an i915 kernel module option.

The term intel_gtt refers to the Intel Graphics Translation Table, a fundamental hardware component and software mechanism within Intel's integrated graphics architecture. It is not a standalone Linux command or executable program that you would typically run from the terminal. Instead, the GTT is a critical part of how the Intel graphics driver (primarily the i915 kernel module) manages memory for the GPU.

The GTT is essentially a page table that maps virtual addresses used by the GPU to physical memory addresses in the system's RAM. This allows the GPU to access system memory efficiently for graphics operations, textures, framebuffers, and other data without requiring a separate, dedicated video RAM chip. Its management is entirely handled by the Linux kernel's Direct Rendering Manager (DRM) subsystem, specifically the i915 driver. User-level interaction with the GTT is typically limited to debugging tools or through indirect configuration of the i915 kernel module.

intel_gtt is not a user-space command. Attempts to execute it directly will fail. Its functionality is entirely kernel-level and deeply integrated with the graphics driver. Direct manipulation of the GTT is typically reserved for kernel developers or advanced debugging, and incorrect changes can lead to system instability, graphics corruption, or system crashes. Normal users should not attempt to modify GTT behavior unless specifically instructed by documentation or support for debugging purposes.

While not a direct command, GTT-related information can often be inspected via the debugfs filesystem, typically mounted at /sys/kernel/debug/. For Intel GPUs, GTT-specific details might be found under /sys/kernel/debug/dri/0/i915_gtt_info (the exact path may vary based on GPU index and kernel version). This file can provide insights into GTT size, usage, and mapping details, primarily useful for debugging graphics driver issues.

The i915 kernel module, which manages the GTT, can be configured using options specified during module loading (e.g., with modprobe) or persistently in /etc/modprobe.d/i915.conf. These options, while not directly named 'GTT parameters', often control memory management aspects that fundamentally rely on the GTT, such as power-saving features or display output configurations.

The concept of a Graphics Translation Table (GTT) has been integral to Intel's integrated graphics architectures for many generations. It emerged as a necessary component to allow the GPU to efficiently access system memory (RAM) directly, rather than relying on a separate, fixed block of dedicated video memory. This design became central to Intel's integrated graphics approach, which prioritizes power efficiency and cost-effectiveness by sharing system resources. The GTT evolved alongside the i915 kernel driver, which has continuously adapted to support new Intel GPU generations and implement features like memory compression, power management, and advanced display capabilities, all heavily relying on the GTT for memory management.

i915 (kernel module), modprobe(8), debugfs(5), drm(7), intel_gpu_tools (package)