This DAL driver supports AMD's Carrizo, Tonga, and Fiji graphics processors atop the AMDGPU kernel driver. This is the driver they will use moving forward for adding new display features to the AMDGPU driver. This code-base also moves the open-source driver closer to being on par with Catalyst and its display capabilities.
The AMDGPU DAL driver finally provides AMD support for implementing the atomic mode-setting API and also provides DisplayPort Multi-Stream Transport (MST), HDMI 2.0 for Carrizo, better PowerPlay integration, better multi-display support, broader support of display dongles, timing synchronization between DisplayPort and HDMI, and other improvements.
This DAL code has been in development for the past several months and is an important part of AMD's plans for allowing Catalyst to become isolated to a user-space blob while riding off the open-source kernel driver. With DAL, the display capabilities of the open-source driver are much closer to feature parity with Catalyst -- for Tonga / Carrizo / Fiji.
This code change adds in over 93,000 lines of new code to the Linux kernel! [287 files changed, 93942 insertions(+), 30 deletions(-)] Hopefully it will get reviewed, tested well, and merged for the Linux 4.6 kernel. For now the massive patch series can be found on dri-devel.