It's possible to use the DMA-BUF renderer without GBM if EGL_MESA_image_dma_buf_export is available in Surfaceless display. It's not the optimal solution, but it works as a fallback when GBM is not available.
Pull request: https://github.com/WebKit/WebKit/pull/14385
Committed 265188@main (81c064ddb418): <https://commits.webkit.org/265188@main> Reviewed commits have been landed. Closing PR #14385 and removing active labels.