Linux 5.9 To Expose Adaptive-Sync / VRR Range Via DebugFS

Written by Michael Larabel in X.Org on 26 June 2020 at 08:32 AM EDT. Add A Comment
For aiding in testing and other purposes, the Variable Refresh Rate (VRR) range for FreeSync/Adaptive-Sync setups will now be exposed via DebugFS with Linux 5.9.

Sent in today was the latest weekly drm-misc-next round of updates. This includes many DRM core changes like NV15 / Q410 / Q401 YUV format support, uncompressed AFBC (Arm Framebuffer Compression) modifier support, and DebugFS reporting of VRR monitor ranges. There are also updates to the various smaller DRM drivers like Lima, Panfrost, and others.

The VRR reporting is exposing the monitor's VRR range minimum and maximum values via DebugFS in a new vrr_range file (e.g. /sys/kernel/debug/dri/0/DP-1/vrr_range). This VRR range reporting addition is mainly intended for debugging/testing purposes and can be used across DRM drivers.

The AMDGPU kernel driver for a while now has been supporting VRR/FreeSync on DisplayPort outputs while Intel is in the process still of their VRR support for Gen11+ graphics hardware.

The full list of changes for this newest DRM-Misc-Next pull to DRM-Next to queue up for Linux 5.9 can be found via dri-devel.
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