AMD's Initial Graphics Updates For Linux 5.3 Include PowerPlay Improvements, HMM Usage

While the Linux 5.2 kernel won't see its debut until July followed by the opening of the Linux 5.3 kernel cycle, the AMD developers sent in today their initial set of staged changes to DRM-Next for queuing their preliminary AMDGPU/AMDKFD driver changes they want to get into this next kernel cycle. There are some notable additions but what we are expecting/hoping for and haven't seen yet is the Navi support.

For the past month we've been seeing the AMD Navi / GFX1010 bits trickle into their LLVM shader compiler back-end but surprisingly no AMDGPU kernel driver patches nor Mesa driver work to this point. But perhaps now that the Radeon RX 5700 series was announced as part of their new "RDNA" architecture branding, perhaps the drop is right around the corner. But it simply isn't ready today for this initial pull request to this staging area of the Direct Rendering Manager drivers.

Though with the RX 5700 series shipping in July, it will mean launch-day customers either need to be building the drivers from source (seeing as the code didn't make it into Linux 5.2 or Mesa 19.1 that will be stable versions then) or be riding the Radeon Software for Linux packaged binary driver stack on a supported enterprise Linux distribution. Anyhow, we'll see when the Navi Linux patches come out in full and on launch-day you can expect to find a full review on Linux to know all about the driver requirements and performance.

What there is to find in this initial AMDGPU/AMDKFD "-next" update for Linux 5.3 are:

- A new "memory utilization" sysfs interface that exposes the real-time memory usage as a percent. (The Phoronix Test Suite sensor framework already supports tapping this new data point.)

- Making use of Heterogeneous Memory Management (HMM) rather than the MMU notifier code for user pages. It's great to see AMD finally moving with the HMM patches.

- Exposing xGMI topology via the AMDKFD compute kernel driver code.

- Fixes around SR-IOV.

- Support for new thermal sensors on some Vega chips.

- Vega PowerPlay improvements.

- GWS barrier support within the AMDKFD compute driver.

- Other clean-ups and improvements.

The complete list of changes can be viewed by this pull request to DRM-Next. Stay tuned to see what else comes for AMDGPU/AMDKFD and the other DRM drivers with Linux 5.3.