Hi,
this RFC patch set implements fbdevdrm, a DRM driver on top of fbdev drivers. I'd appreciate feedback on the code and the idea in general.
The fbdev subsystem is considered legacy and will probably be removed at some point. This would mean the loss of a signifanct number of drivers. Some of the affected hardware is probably not in use any longer, but some hardware is still around and provides good(-enough) framebuffers.
OTOH, userspace programs that want to support a wide range of graphics hardware have to implement support for both DRM and fbdev interfaces. Such software would benefit from a single interface.
The fbdevdrm driver provides a way of running drivers for old and new hardware from the DRM subsystem and interfaces.
It's not intended to add new features or drivers to fbdev. Instead fbdevdrm is supposed to be a template for converting fbdev drivers to DRM. It contains a number of comments (labeled 'DRM porting note') that explain the required steps. The license is fairly liberal to allow for combination with existing fbdev code.
I tested the current patch set with the following drivers: atyfb, aty128fb, matroxfb, pm2fb, s3fb, savagefb, sisfb, tdfxfb and tridentfb. I was able to successfully start with fbcon enabled and then run weston or X.
Thomas Zimmermann (11): drm/fbdevdrm: Add driver skeleton drm/fbdevdrm: Add fbdevdrm device drm/fbdevdrm: Add memory management drm/fbdevdrm: Add file operations drm/fbdevdrm: Add GEM and dumb interfaces drm/fbdevdrm: Add modesetting infrastructure drm/fbdevdrm: Add DRM <-> fbdev pixel-format conversion drm/fbdevdrm: Add mode conversion DRM <-> fbdev drm/fbdevdrm: Add primary plane drm/fbdevdrm: Add CRTC drm/fbdevdrm: Detect and validate display modes
drivers/gpu/drm/Kconfig | 2 + drivers/gpu/drm/Makefile | 1 + drivers/gpu/drm/fbdevdrm/Kconfig | 13 + drivers/gpu/drm/fbdevdrm/Makefile | 11 + drivers/gpu/drm/fbdevdrm/fbdevdrm_bo.c | 276 ++++++++ drivers/gpu/drm/fbdevdrm/fbdevdrm_bo.h | 58 ++ drivers/gpu/drm/fbdevdrm/fbdevdrm_device.c | 96 +++ drivers/gpu/drm/fbdevdrm/fbdevdrm_device.h | 55 ++ drivers/gpu/drm/fbdevdrm/fbdevdrm_drv.c | 347 +++++++++ drivers/gpu/drm/fbdevdrm/fbdevdrm_format.c | 441 ++++++++++++ drivers/gpu/drm/fbdevdrm/fbdevdrm_format.h | 26 + drivers/gpu/drm/fbdevdrm/fbdevdrm_modes.c | 195 +++++ drivers/gpu/drm/fbdevdrm/fbdevdrm_modes.h | 53 ++ drivers/gpu/drm/fbdevdrm/fbdevdrm_modeset.c | 746 ++++++++++++++++++++ drivers/gpu/drm/fbdevdrm/fbdevdrm_modeset.h | 38 + drivers/gpu/drm/fbdevdrm/fbdevdrm_primary.c | 498 +++++++++++++ drivers/gpu/drm/fbdevdrm/fbdevdrm_primary.h | 27 + drivers/gpu/drm/fbdevdrm/fbdevdrm_ttm.c | 202 ++++++ drivers/gpu/drm/fbdevdrm/fbdevdrm_ttm.h | 35 + 19 files changed, 3120 insertions(+) create mode 100644 drivers/gpu/drm/fbdevdrm/Kconfig create mode 100644 drivers/gpu/drm/fbdevdrm/Makefile create mode 100644 drivers/gpu/drm/fbdevdrm/fbdevdrm_bo.c create mode 100644 drivers/gpu/drm/fbdevdrm/fbdevdrm_bo.h create mode 100644 drivers/gpu/drm/fbdevdrm/fbdevdrm_device.c create mode 100644 drivers/gpu/drm/fbdevdrm/fbdevdrm_device.h create mode 100644 drivers/gpu/drm/fbdevdrm/fbdevdrm_drv.c create mode 100644 drivers/gpu/drm/fbdevdrm/fbdevdrm_format.c create mode 100644 drivers/gpu/drm/fbdevdrm/fbdevdrm_format.h create mode 100644 drivers/gpu/drm/fbdevdrm/fbdevdrm_modes.c create mode 100644 drivers/gpu/drm/fbdevdrm/fbdevdrm_modes.h create mode 100644 drivers/gpu/drm/fbdevdrm/fbdevdrm_modeset.c create mode 100644 drivers/gpu/drm/fbdevdrm/fbdevdrm_modeset.h create mode 100644 drivers/gpu/drm/fbdevdrm/fbdevdrm_primary.c create mode 100644 drivers/gpu/drm/fbdevdrm/fbdevdrm_primary.h create mode 100644 drivers/gpu/drm/fbdevdrm/fbdevdrm_ttm.c create mode 100644 drivers/gpu/drm/fbdevdrm/fbdevdrm_ttm.h
-- 2.21.0