At XDC2020 (X.Org Developers Conference), it was announced that ARM has joined the development process of the project panfrost (which develops an open driver for the Mali video core).
For those who are unaware of the Panfrost controller, you should know that was founded in 2018 by Alyssa Rosenzweig at Collabora and has evolved so far based on reverse engineering of the original ARM controllers.
Currently, the driver supports chips based on Midgard (Mali-T6xx, Mali-T7xx, Mali-T8xx) and Bifrost (Mali G3x, G5x, G7x) microarchitectures.
For the Mali 400/450 GPU used in many older ARM-based chips, the Lima driver is being developed separately.
This reverse-engineered driver supports the Mali GPU's Midgard and Bifrost generation, as an almost completely independent, self-funded endeavor.
We take great pride in this work and the fact that it has high performance, good levels of functionality, and a high level of conformance to specification.
With this announcement, ARM has expressed its willingness to provide to controller developers the information and documentation needed to better understand the hardware and focus on development, without wasting time solving puzzles in the reverse engineering process of binary drivers.
However, reverse engineering necessarily comes with overhead, as we need to spend time figuring out how the hardware actually works, including the most optimal way to perform various operations and particular hardware quirks.
Previously, this was the case with Qualcomm's connection to work on the Freedreno project, developing a free driver for the Qualcomm Adreno GPU.
Arm is now working together with Collabora to provide us with information and documentation that enables us and the community to understand the hardware.
Collabora continues our effort to make Panfrost work on all devices of these generations, towards maximum performance, full compliance with specifications and the largest possible set of features. While we have already done so, Arm support allows us to accelerate this work and provide the best possible driver with a long-term commitment to support.
And it is that for a long time many of the drivers are known GPU for processors ARMs are closed source, which makes development difficult open drivers and especially if errors are found they can take a long time to be corrected.
The developer community has long tried to reverse engineer GPU drivers with projects like Freedreno (Qualcomm Adreno), Etnaviv (Vivante), as well as Lima and Panfrost for Arm Mali's GPUs.
Several years ago, Arm's management was not interested in assisting with the development of open source GPU drivers for Mali GPUs, but as Phoronix pointed out, Alyssa Rosenzweig, a graphics software engineer employed by Collabora, explained that the development Panfrost was now made in association with Arm.
ARM participation will help bring stability to the implementation to ubiquity and will better support GPU Mali-specific internal instructions by providing first-hand information on the chip architecture.
The availability of internal documentation will also ensure maximum performance, full specification compliance, and coverage of all available Midgard and Bifrost GPU capabilities.
The first changes based on information received from ARM they have already been entered into the controller code base. In particular, work has been done to bring instruction packaging operations to canonical form and to completely redesign the disassembler to more accurately reflect the Bifrost GPU instruction set architecture and conformance to accepted ARM terminology.
Finally the controller is expected to have a drastic improvement in a matter of no time, and this announcement may encourage more developers.
If you want to know more about the note, you can consult the original statement by going to the following link.