Older AMD GPUs Score Another Open-Source Driver Win From Valve: DRM Format Modifiers

Timur Kristóf of Valve's Linux open-source graphics driver team isn't done driving new improvements to aging AMD GCN 1.0/1.1 era graphics cards on Linux. Beyond enhancing display support for older APUs, transitioning GCN 1.0/1 GPUs from the legacy Radeon driver to modern AMDGPU driver, and a host of other fixes and optimizations for these old GPUs going back to the Radeon HD 7000 series, he has another notable addition that was announced today. These original GCN graphics cards with pending patches to the AMDGPU kernel driver and Mesa user-space can now allow for DRM format modifiers.

Timur Kristóf took to implementing DRM format modifiers for AMD GFX6 through GFX8 era GPUs. This covers from original GCN 1.0 GPUs up through the GFX8 Polaris and Fiji series, which all lacked DRM format modifiers. DRM format modifiers provide details on tiling, compression, and other attributes for image buffers. Depending upon the layout it can also help with better performance and other more versatile use-cases. DRM format modifiers support can allow Vulkan-powered Wayland compositors, compositors running on the Zink OpenGL-on-Vulkan layer, interoperability between different graphics APIs, and more.

Timur Kristóf wrote with the AMDGPU driver patch series implementing DRM format modifiers for GFX6 through GFX8 graphics IP:

"GFX6-8 are the oldest GPUs supported by the amdgpu kernel driver, and the last ones that didn't support DRM format modifiers until now.

On GFX6-8, the GFX block can only use pre-determined tiling modes which are programmed by the kernel according to the tiling mode table. The new modifiers encode all the details needed for tiling on these GPUs.

Supporting DRM format modifiers on GFX6-8 will unblock many things in the Linux graphics ecosystem that previously either didn't work on these GPUs or had to implement fallbacks. For example, compositors written in Vulkan or compositors running on Zink, interop between different APIs (eg. VAAPI / OpenGL / Vulkan) etc."

In addition to those AMDGPU Linux kernel driver patches there is also this Mesa merge request for implementing the DRM format modifiers support for these older AMD Radeon graphics processors in the user-space RADV/RadeonSI driver side.