Tag Archives: APUs

GFX1013 Target Added To LLVM 13.0 For RDNA2 APUs


LLVM --

Merged last week to mainline LLVM 13.0 was the new “GFX1013” target for the AMDGPU shader compiler. Well, it landed twice as at first had to be reverted after breaking the build bots / sanitizer testing.

GFX1013 is the newest graphics target for AMDGPU LLVM. Notable out of the commit is confirmation that it’s for an RDNA2-based APU. Like with the other RDNA2 GPUs, the compiler target does confirm that GFX1013 does feature ray-tracing support with the BVH ray-tracing instructions being present.

Current rumors put the Ryzen 6000 series APUs as featuring Zen 3 (or Zen 3+) CPU cores with RDNA2 graphics. These “Rembrandt” APUs are also expected to launch with DDR5 memory support. Some more recent rumors put the Rembrandt APUs as having up to 12 CUs. In any case it will be great to see AMD APUs coming with RDNA2 in moving beyond Vega graphics.

The LLVM 13.0 compiler stack should be out as stable in September while waiting for the rest of the open-source AMD Radeon Linux graphics stack to get ironed out for AMD’s next-gen APUs.


Mesa Radeon Vulkan Driver Sees ~30% Performance Boost For APUs


MESA --

Mesa’s RADV Radeon Vulkan driver just saw a big performance optimization land to benefit APUs like Raven Ridge and Picasso, simply systems with no dedicated video memory.

The change by Feral’s Alex Smith puts the uncached GTT type at a higher index than the visible vRAM type for these configurations without dedicated vRAM, namely APUs.

This fix boosted the average frame-rate for the Rise of the Tomb Raider Linux port by around 30% and other Feral Vulkan-powered Linux games as well as other titles.

The good news is due to the significant boost to performance and its high exposure, this “fix” to the RADV driver is marked as a candidate for back-porting to the Mesa 19.2 series rather than needing to wait until next quarter’s Mesa 19.3.

Or if you are building your own Mesa, it’s just a dozen line patch yielding the double digit Vulkan driver performance improvements.


AMD Sends Out Initial Linux Driver Support For “Renoir” APUs


AMD --

AMD is striking well over the past month with their Linux hardware bring-up. In the past month we’ve seen the Navi 10/12/14 support get in order for Linux as well as support for the future Vega-based Arcturus GPU and now we see the initial enablement patches for their next-generation APUs, Renoir.

Sent out today was the initial 27 patches amount to around two thousand lines of code (roughly half of which is just header files) for bringing up this next-gen AMD APU.

Renoir is the successor to current AMD Picasso APUs and are said to be based on the new Zen 2 architecture while incorporating a Navi GPU… Well, at least originally what rumors/leaks reported. These code patches indicate Renoir to be based on Raven/Vega as opposed to Navi. Not a whole lot is known about Renoir publicly and are not expected to hit the shelves until 2020.

Renoir is based on Navi (or actually Vega?) so it isn’t a whole lot of new code from the AMDGPU kernel driver side, but still, we aren’t accustomed to seeing this Linux driver support so early in advance of launch (potentially ~6+ months). It could be a sign that there could be some interesting design wins or Chromebooks warranting good Linux support at launch or it could just be that they’ve hit a good punctual stride on new platform enablement, but whatever the case is it’s certainly welcomed, especially after the very bumpy Raven Ridge experience on Linux.

These patches do confirm VCN 2.0 support on Renoir while most of he code changes come down to slight differences around power management / clock gating, golden register settings, and firmware bits. The AMDGPU code though does seem to indicate this as Vega-based rather than Navi as was rumored. So unless they end up marketing it weirdly (just like Kabylake-G with VegaM really being Polaris), that is what’s happening.

For now at least Renoir’s graphics is just represented by a single PCI ID, 0x1636.

This currently experimental (hidden behind feature flag) AMD Renoir support should be on its way to DRM-Next soon for premiering in Linux 5.4 while over the coming kernel cycles should stabilize and be flipped on by default, hopefully well ahead still of the hardware’s expected launch.