Qualcomm MSM Driver With Linux 5.19 Adds DSC, Preps For Mesa Driver Within A VM

MSM DRM driver and Freedreno creator Rob Clark continues leading the charge on open-source Qualcomm Adreno graphics/display support for Linux in this effort that started out as a reverse-engineering project years ago. This past week Rob sent in the last batch of MSM Direct Rendering Manager driver updates intended for the Linux 5.19 kernel.

Among the MSM driver changes for DRM-Next with Linux 5.19 include:

- GPU virtual address / user-space allocated IOVA support. The motivation here by Rob Clark is for allowing native user-space Mesa driver to run within a virtualized guest (VM). The associated native Mesa driver code is Freedreno Gallium3D and TURNIP for Vulkan.

- DPU support for Display Stream Compression (DSC). The VESA-backed Display Stream Compression standard is for providing visually lossless, low-latency compression between the host and HDMI/eDP/DSI/HDMI display panel(s) for bandwidth savings.

- Inline rotation support for display with the Snapdragon SC7280.

- Wide bus support for newer chipsets. The "wide bus" feature with newer hardware allows moving two pixels of data per pixel clock to interface to display rather than one pixel. The wide bus feature increases the bus width from 32 to 64 bits. Wide bus support in part is necessary for then going on to enable 4K resolution support with the MSM driver.

- Embedded DisplayPort (eDP) support.

- Merging of the DPU1 and DP5 MDSS driver code.

- Various other clean-ups and bug fixes.

More details on this open-source Qualcomm graphics/display driver changes for Linux 5.19 can be found via this pull.