Abstract:
Qualcomm recently submitted the first batch of open source Linux kernel driver patches for the new Adreno 850 GPU, and it was only one day from the official announcement of the chip to the relevant code entering the Linux kernel development process. This means that Qualcomm is further accelerating the development of open source drivers for the new generation of Adreno GPUs, and even starting to promote mainline Linux support immediately after the official debut of the hardware.
The target platform supported by this driver is the Qualcomm SoC code-named "Hawi", which is currently generally believed by the industry to be the just-released Snapdragon 8 Elite Extreme Gen 6. The processor uses the new Adreno 850 graphics core, and Qualcomm engineers submitted the relevant GPU initialization code to the Linux kernel mailing list the day after the chip was released.
In fact, the Hawi platform did not suddenly appear in the Linux community. In the past few months, Qualcomm has successively submitted other hardware support codes for Hawi to the Linux kernel, so this Adreno 850 GPU driver patch is actually a further improvement based on previous platform support.
The patch submitted this time mainly targets the MSM graphics driver in the Linux kernel, which is the mainline open source driver framework of Qualcomm Adreno GPU. Although it is still in the early stages of development and code review, the significance is that Adreno 850 has begun to enter the Linux mainline driver system, instead of waiting until the product is launched long before it is supplemented by the community.
In addition to Adreno 850, this batch of patches also adds preliminary support for Adreno 845. Adreno 845 is codenamed "Maili". Its hardware architecture is highly similar to Adreno 850, but it lacks a new MALU matrix core. Therefore, Qualcomm can establish driver support for the two GPUs while sharing a large amount of basic code.
Adreno 850 belongs to Qualcomm’s new generation Adreno 8xx GPU architecture. According to the information disclosed in this patch, it shares part of the core architecture and slice design with the previous generation Adreno 840, while also making a number of hardware-level improvements.
One of the important changes is the new MALU matrix core. Qualcomm uses this hardware unit to accelerate specific types of matrix calculation tasks, which is also one of the important changes in the Adreno 850 compared to previous GPU architecture. However, no detailed data has been released yet on the specific application scenarios of MALU, how much performance improvement it can bring, and which software APIs it will eventually open to applications.
Qualcomm said that MALU related support needs to be further added in the future, and it not only involves the Linux kernel driver, but also requires the cooperation of the Mesa user space graphics driver. Therefore, even if the basic GPU support of Adreno 850 enters the Linux mainline this time, the MALU matrix computing power will not be available immediately.
In addition to the computing unit, the power management system of Adreno 850 has also been adjusted. The patch shows that the GPU adds a new power rail to supply power to some GPU hardware modules. At the same time, the GPU Management Unit, or GMU, which is responsible for GPU power state management, now has an independent GDSC power gating area, and this part is powered by another power rail called MxG.
These changes may seem like low-level hardware details, but they are very important for Linux drivers. The GPU not only needs to complete graphics calculations, but also needs to dynamically adjust voltage, frequency and power supply status between idle, low load and high load states. Therefore, changes in power management hardware must be handled correctly in the kernel driver, otherwise it may affect power consumption, stability, and even normal GPU operation.
The current batch of Adreno 850 and Adreno 845 codes have not yet entered the officially released Linux kernel version and are still in the code review stage. At the same time, in order for devices equipped with Adreno 850 to truly achieve complete hardware acceleration under Linux, firmware, Mesa user space drivers and display-related support must be in place.
The user space support of Qualcomm Adreno GPU in the Linux ecosystem mainly relies on Freedreno and Turnip in the Mesa project. Freedreno is responsible for graphics interfaces such as OpenGL, while Turnip is responsible for Vulkan. For Adreno 850, subsequent Mesa support will determine the final Linux graphics performance together with this kernel driver work.
Currently, Qualcomm's testing of Adreno 850 is still in the very early bring-up stage, so this patch cannot be understood as "Adreno 850 can already run normally under Linux." The driver code has just begun to enter the mainline development process, and there are still many steps to go before ordinary users can obtain full graphics acceleration on actual devices.
However, judging from the time point, Qualcomm’s actions are still quite active. In the past, new GPUs often had to wait a long time to obtain a complete open source Linux driver. However, the Adreno 850 has a Linux kernel support patch only one day after the hardware was officially announced, indicating that Qualcomm is significantly increasing its investment in mainline Linux and open source graphics ecology.
This trend is basically consistent with Qualcomm’s recent direction of promoting Snapdragon X2 Linux support. Qualcomm is currently not only continuing to submit Linux drivers for the Adreno X2-85 GPU on the PC platform, but is also promoting Freedreno and Turnip support in Mesa, so that Snapdragon X2 will gradually have a complete Linux graphics stack.
For Linux developers, the fact that Adreno 850 can enter the open source driver development process so quickly means that the hardware support cycle of Qualcomm's flagship mobile platform in the Linux ecosystem may be further shortened in the future. For the entire open source community, this also means that developers can obtain the hardware information and driver code of the new GPU earlier, thereby simultaneously promoting the graphics stack adaptation before and after the new chip is launched.
At present, the Linux support of Adreno 850 is still in a very early stage, and functions such as MALU matrix core, Mesa graphics driver, firmware and display output still need to be improved in the future. However, Qualcomm submitted a GPU open source driver patch just one day after the release of the new chip, which has shown that it is trying to keep the new generation of Adreno GPU more closely synchronized with the mainline Linux ecosystem from the beginning of the product release.
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