Nouveau Preparations For HDMI 2.1 DSC, AMD HDMI FreeSync Fixes For Linux 7.4

Last week's set of DRM-Misc-Next changes submitted to DRM-Next with targeting the upcoming Linux 7.4 kernel cycle features HDMI 2.1 related work for both the AMDGPU kernel driver as well as the Nouveau open-source NVIDIA driver.

The Nouveau changes submitted as part of last week's DRM-Misc-Next pull includes supporting a 2.147 GHz pixel clock for Blackwell GPUs. This goes along with other recent display-related fixes for Blackwell on Nouveau that made it into Linux 7.3 as pure fixes. Nouveau needs to support a 2.147GHz pixel clock and higher for Blackwell GPUs in preparation for HDMI 2.1 Display Stream Compression (DSC) support. Currently with Nouveau uncompressed HDMI FRL is only hitting around 1.78GHz but the higher limit will be reached once DSC is all wired up. Whether Nouveau DSC support will be ready to go in time for the Linux 7.4 kernel cycle remains to be seen at the moment.

Also notable with this pull request is finally enabling Nouveau atomic mode-setting by default. Great to see that work finally achieved and catching up with the other Linux DRM drivers long using atomic mode-setting by default.

The DRM-Misc-Next pull also features some bits worth mentioning on the AMDGPU side too. There are some DRM EDID parser fixes for handling the AMD VSDB FreeSync functionality with some display manufacturers only advertising their Variable Refresh Rate (VRR) capabilities in the AMD Vendor-Specific Data Block (VSDB) block. Currently the common Linux DRM EDID parser is not handling some versions of the AMD VSDB, which is being addressed in Linux 7.4 to better detect VRR capabilities.

More details on these latest Linux DRM driver feature changes destined for Linux 7.4 can be found via this drm-misc-next pull.