GNU Linux-Libre 4.2 Takes Aim At AMDGPU & Intel's DRM Drivers

Written by Michael Larabel in Linux Kernel on 30 August 2015 at 10:16 PM EDT. 41 Comments
LINUX KERNEL
Just hours after the release of Linux 4.2 was the update from the Free Software Foundation community for the GNU Linux-Libre 4.2 kernel. This deblobbed version of the Linux kernel has particularly criticized the new AMDGPU DRM driver and the Intel i915 driver this cycle.

The Linux-libre 4.2 announcement reads:
Many new drivers required cleaning of their blob-requesting-and-loading machinery. Various others needed deblobbing updates due to blob name changes and false positives.

The greatest new offender is amdgpu that, like radeon, refuses to work at all without blobs, even though in theory it could offer degraded functionality.

The other unfortunate surprise is the traditionally Freedom-friendly i915 driver, that, in 4.2 upstream, attempts to load blobs on some recent variants.
The AMDGPU gripe is that with this new driver for Tonga/Carrizo/Fiji and future AMD GPUs, there is a requirement on microcode/firmware files that AMD produces as binary-only. The files are available for all those to use, but they aren't open-source, just as they aren't with the Radeon DRM driver on hardware generations going back a number of years. Thus if you want a 100% free software stack, the driver doesn't suit your needs. Without these files, you won't get any hardware acceleration.

In terms of the i915 criticism, that is due to Skylake and Broxton hardware requiring firmware blobs while in the past there wasn't such binary blobs needed for hardware initialization and acceleration. Other future Intel graphics hardware will also be going this route.

The Nouveau situation also hasn't become any different with the GeForce GTX 900 "Maxwell" series now requiring firmware blobs and in this case must be signed by NVIDIA Corp. Still waiting for NVIDIA to release those images, but Nouveau with Linux 4.3 will gain support for loading NVIDIA's firmware files.

In other words, all of the recent GPUs targeting x86 PCs are requiring binary-only firmware/microcode in one form or another if you want 3D acceleration -- even for "open source" drivers. With the GNU Linux-Libre kernel stripping out any binary-only firmware files and the support for loading binary blobs, this kernel isn't for the faint hearted unless you've meticulously selected the components for your system as it takes the Linux kernel to an extreme.
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Michael Larabel is the principal author of Phoronix.com and founded the site in 2004 with a focus on enriching the Linux hardware experience. Michael has written more than 20,000 articles covering the state of Linux hardware support, Linux performance, graphics drivers, and other topics. Michael is also the lead developer of the Phoronix Test Suite, Phoromatic, and OpenBenchmarking.org automated benchmarking software. He can be followed via Twitter, LinkedIn, or contacted via MichaelLarabel.com.

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