Open Source Summit Europe 2022

The Linux frame buffer device (fbdev) subsystem was deprecated in 2015. Since then, no new drivers are accepted, and all new graphics drivers must use the DRM/KMS subsystem instead, which was originally conceived to support accelerated 3D graphics on high-end desktop PCs. Still, upstream Linux supports more than 100 fbdev drivers, most of them without a counterpart in the DRM subsystem, and thus waiting for conversion to DRM (or for a darker fate). Fbdev drivers for new hardware can also be found in vendor BSPs, with no hopes of ever being upstreamed. In this presentation, targeting legacy and embedded kernel graphics developers, Geert will discuss the issues hindering the conversion of your favorite fbdev driver to DRM. He will present the steps that have and are being taken, balance the gains and losses, and suggest areas for future improvement, based on his experience of converting fbdev drivers and improving DRM, 18 years after he stepped down as an fbdev maintainer. While most of the remaining fbdev drivers are for legacy hardware, improving DRM for their needs will benefit contemporary embedded systems, too. Low-end platforms may not support 3D acceleration or deep-color displays, but are subject to stringent memory, CPU, and power restrictions.