Linux kernel and user-space frameworks for display and graphics are intertwined and the software stack can be quite complex with many layers and different standards/APIs. On the kernel side, the display and graphics portions are split with each having their own APIs. However, both are commonly referred to as a single framework: DRM/KMS.
This split is advantageous, especially for SoCs that often have dedicated hardware blocks for display and graphics. The display pipeline driver responsible for interfacing with the display uses the kernel mode setting (KMS) API and the GPU responsible for drawing objects into memory uses the direct rendering manager (DRM) API. Both APIs are accessed from user-space through a single device node.
A brief overview of the DRM is provided but the focus is on KMS as there is no GPU present in the design.