Virtual KMS Driver To Work On Virtual Refresh Rate Support (FreeSync)

Written by Michael Larabel in X.Org on 10 November 2019 at 11:45 AM EST. 1 Comment
Over the past year and a half the VKMS Linux DRM driver has come together as the "virtual kernel mode-setting" implementation for headless systems and other environments not backed by a physical display. Interestingly being tacked on their TODO list now is VRR (Variable Refresh Rate) support. Separately, the prominent VKMS developer is now employed by AMD.

The VKMS code got into shape originally back in 2018 when Rodrigo Siqueira was a student participating in Google Summer of Code. Since this past August, however, he began working for AMD in Toronto as a software engineer on their new display technologies, new ASIC/hardware bring-up, and other driver work focused on the display side. He is though still working on the open-source VKMS effort albeit not as much as previously and doesn't appear to be doing so in an official capacity for AMD.

Stemming from last month's X.Org Developer's Conference in Montreal (XDC 2019), Rodrigo has decided to work on adding adaptive refresh rate / variable rate refresh (VRR) to the Virtual KMS code. Also as part of his VKMS plans is support for dynamic connectors for testing virtual setups like multi-stream transport (MST).

VRR / Adaptive Refresh Rate support within VKMS could be used for testing purposes and working out new Linux display APIs/implementations around VRR without actually having any VRR-capable display but doing so virtually.

There is no code for VRR / Adaptive Refresh Rate support for VKMS yet and is just a plan by Siqueira, but interesting nevertheless. More details on his personal blog.
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