AMD Sends Out Patches Enabling New "DCN 3.5" GPU Display Block

Last week AMD sent out initial patches for enabling the "GFX 11.5" graphics IP under Linux for this presumed RDNA3 refresh that is likely for their next-gen Ryzen 8000 series APUs. Today AMD open-source Linux driver engineers sent out DCN 3.5 patches as an updated version of their Display Core Next IP.

It looks along with the updated graphics engine for the RDNA3 refresh will be updated DCN3 display capabilities. A set of 35 patches were posted today to the mailing list for enabling the DCN 3.5.0 display block. These patches amount to more than 101k lines of new code, albeit the vast majority of that is auto-generated C header files as is routine for the AMDGPU driver.

This patch series gets the DCN 3.5 display support going for what looks like will be AMD's next-gen APUs with it looking unlikely any RDNA3 refresh (GFX11.5 + DCN3.5) type configuration will work its way out to discrete graphics cards.

As part of this patch series is introducing "DML2". DML as it exists now in the AMDGPU DC display space is around their Display Mode Library while DCN 3.5+ moves to DML2 as a new version that adds display mode verification and is now written from the ground-up in C code to make it easier to read and maintain. Being all in C code now should make it also more portable across CPU architectures compared to the current AMDGPU DC woes with bits of hand-written Assembly and other problems that have come up.

Given the timing of these patches this DCN 3.5 display support isn't expected to be upstreamed to the mainline kernel until Linux 6.7 later in the year.