Hi Thomas, On Fri, Oct 22, 2021 at 03:28:20PM +0200, Thomas Zimmermann wrote: > Enable FB_DAMAGE_CLIPS with simpledrm for improved performance and/or > less overhead. With this in place, add support for virtual screens > (i.e., framebuffers that are larger than the display resolution). This > also enables fbdev panning and page flipping. > > After the discussion and bug fixing wrt to fbdev overallocation, I > decided to add full support for this to simpledrm. Patches #1 to #5 > change the format-helper functions accordingly. Destination buffers > are now clipped by the caller and all functions support a similar > feature set. This has some fallout in various drivers. > > Patch #6 change fbdev emulation to support overallocation with > shadow buffers, even if the hardware buffer would be too small. This change is very welcome - I hope it will solve the problem Alistair experience - see: https://lore.kernel.org/all/CAKmqyKPCP45O5_gjCFwUs8jU4NrDnjAeLs7OYAE4j-LEUw+Hzg@xxxxxxxxxxxxxx/ Sam > > Patch #7 and #8 update simpledrm to enable damage clipping and virtual > screen sizes. Both feature go hand in hand, sort of. For shadow- > buffered planes, the DRM framebuffer lives in system memory. So the > maximum size of the virtual screen is somewhat arbitrary. We add two > constants for resonable maximum width and height of 4096 each. > > Patch #9 adds documentation and a TODO item. > > Tested with simpledrm. I also ran the recently posted fbdev panning > tests to make sure that the fbdev overallocation works correctly. [1] > > [1] https://lists.freedesktop.org/archives/igt-dev/2021-October/036642.html > > Thomas Zimmermann (9): > drm/format-helper: Export drm_fb_clip_offset() > drm/format-helper: Rework format-helper memcpy functions > drm/format-helper: Add destination-buffer pitch to drm_fb_swab() > drm/format-helper: Rework format-helper conversion functions > drm/format-helper: Streamline blit-helper interface > drm/fb-helper: Allocate shadow buffer of surface height > drm/simpledrm: Enable FB_DAMAGE_CLIPS property > drm/simpledrm: Support virtual screen sizes > drm: Clarify semantics of struct > drm_mode_config.{min,max}_{width,height} > > Documentation/gpu/todo.rst | 15 ++ > drivers/gpu/drm/drm_fb_helper.c | 2 +- > drivers/gpu/drm/drm_format_helper.c | 236 ++++++++++---------- > drivers/gpu/drm/drm_mipi_dbi.c | 6 +- > drivers/gpu/drm/gud/gud_pipe.c | 14 +- > drivers/gpu/drm/hyperv/hyperv_drm_modeset.c | 5 +- > drivers/gpu/drm/mgag200/mgag200_mode.c | 4 +- > drivers/gpu/drm/tiny/cirrus.c | 24 +- > drivers/gpu/drm/tiny/repaper.c | 2 +- > drivers/gpu/drm/tiny/simpledrm.c | 41 +++- > drivers/gpu/drm/tiny/st7586.c | 2 +- > include/drm/drm_format_helper.h | 58 ++--- > include/drm/drm_gem_atomic_helper.h | 18 ++ > include/drm/drm_mode_config.h | 13 ++ > 14 files changed, 254 insertions(+), 186 deletions(-) > > -- > 2.33.0
