Intel Posts Patches Bringing Up DG2/Alchemist Discrete Video Memory For Linux

Since the start of July we've seen Intel beginning Linux support patches for their DG2 graphics card that is now known by the "Alchemist" codename. There's been several rounds of DG2 patches since they started publicly pushing out the code -- including some notable work like DisplayPort 2.0 bring-up -- while sent out this Sunday is another important piece of the puzzle: getting the device memory (the dedicated vRAM) actually working with the open-source driver.

Getting the device local memory working for DG2/Alchemist is obviously critical and also one of the areas where the bring-up around DG1 took a while since the open-source Intel Linux graphics driver previously has only ever needed to deal with system memory for the integrated graphics of prior generations. So since they began the DG1 bring-up they've had to restructure the driver to introduce the notion of device local memory while retaining the shared system memory code, beginning to work on TTM memory management support for managing that device memory, and various other changes now that Intel is entering the discrete graphics space with their forthcoming ARC graphics cards.

Given all the DG1 prepping to this stage, supporting the device memory isn't all that invasive with just some 500 or so new lines of code for DG2/Alchemist and any other Gen12.5+ platforms with device memory. The minimum page size has been bumped to 64KB, there are changes around the compression control state, and various other low-level changes.

The patches for this DG2/Alchemist device memory support can be found on the driver mailing list. Due to the timing of this work, these patches won't be mainlined until the Linux 5.16 cycle.