Intel OTC Still Playing With Atomic Mode-Setting

A second round of patches have emerged for the open-source Intel Linux graphics driver to support atomic mode-setting with the kernel.

Ville Syrjala of Intel's Open-Source Technology Center has been working on Intel Linux atomic mode-setting support for the past few months. In late May he originally published a set of six patches for their DRM driver to handle this atomic mode-setting idea while one month later he's onto round two and this time with ten patches.

Their plan for this DRM atomic mode-setting is to have just one exposed kernel ioctl that can be fed a list of mode-setting related properties. The driver itself can then determine if all the properties could function together and would be supported by the given graphics processor and display(s). If everything jives, the properies could then be applied.

With just one ioctl and treating everything as a property, it's meant to be extensible for the long-term with allowing new features in the future. Connector lists and other tables can be treated as a property with the ioctl accepting blobs.

If my memory serves me, the first time I heard Intel talk much about their atomic mode-setting plans was back in February in Brussels during FOSDEM. Jesse Barnes mentioned this design for handling mode-setting changes and other property changes within Wayland, since there is not any X RandR (Resize and Rotate) extension.

Atomic mode-setting was also talked about in the past when it came to KGDB as a kernel debugging shell over KMS.

This second round of Intel atomic mode-setting patches can be found on dri-devel. Syrjala mentions that this code is still very much a work in progress.