Hello all, For a while now, I've been working to fix tearing with PRIME. I have a working solution that requires changes to DRM, libdrm, and the X server. I've also implemented sink support in the modesetting driver, and source support in the NVIDIA proprietary driver. These DRM patches ultimately provide a new ioctl, DRM_IOCTL_PRIME_PAGE_FLIP, that sets up a fence on a PRIME member's DMA-BUF reservation object with a callback to schedule a flip to the associated fb. With my synchronization patches to X, it is possible to export two shared buffers per crtc instead of just one. The sink driver uses DRM_IOCTL_PRIME_PAGE_FLIP to set up fences on each of these buffers. When the source driver is done presenting on a given buffer, it signals the associated fence, and the sink flips on the next vblank. In the page flip event handler, the sink driver uses the ioctl to set up another fence, and explicitly requests a present on the current back buffer using a new function in the X ABI. Thus, flips are driven by presents, presents are driven by flips, and the whole thing conforms to the sink's refresh rate. Right now, the part that signals the fence is a vendor-specific ioctl, but I'm open to factoring it out into a core DRM ioctl and DRM driver function helper like DRM_IOCTL_PRIME_PAGE_FLIP if it would make implementing source support easier for open source drivers. Due to the lack of asynchronous atomic modesetting support on i915 (the sink of most hybrid graphics systems,) I've implemented this on top of the old page_flip method. Perhaps an atomic modesetting / nuclear pageflip based method would be better, but it wouldn't be as viable without widespread asynchronous support. I'm willing to implement an atomic modesetting version if required, but it's less clear what the best implementation would be: perhaps a fence property that defers asynchronous commits. There are enough ways to do it that it probably warrants prior discussion. Nonetheless, this method is necessary at least as a fallback until i915 supports asynchronous atomic modesetting. To give some greater context, I've uploaded my branches for DRM, libdrm, and the X server to Github. I'll move forward with upstreaming the libdrm and X changes if and when these DRM patches go in. DRM Tree: https://github.com/GoinsWithTheWind/drm-prime-sync libdrm Tree: https://github.com/GoinsWithTheWind/libdrm-prime-sync X Tree: https://github.com/GoinsWithTheWind/xserver-prime-sync Thanks, Alex @ NVIDIA Linux Driver Team agoins (6): drm: factor out drm_mode_page_flip_ioctl() drm: generalize drm_prime_lookup drm: add fence context drm: add drm_gem_prime_page_flip() helper drm: add prime_page_flip() driver function drm: add DRM_IOCTL_PRIME_PAGE_FLIP drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c | 1 + drivers/gpu/drm/armada/armada_drv.c | 1 + drivers/gpu/drm/drm_crtc.c | 90 ++++++++---- drivers/gpu/drm/drm_internal.h | 2 + drivers/gpu/drm/drm_ioctl.c | 1 + drivers/gpu/drm/drm_prime.c | 213 ++++++++++++++++++++++++++-- drivers/gpu/drm/exynos/exynos_drm_drv.c | 1 + drivers/gpu/drm/i915/i915_drv.c | 1 + drivers/gpu/drm/imx/imx-drm-core.c | 1 + drivers/gpu/drm/msm/msm_drv.c | 1 + drivers/gpu/drm/nouveau/nouveau_drm.c | 1 + drivers/gpu/drm/omapdrm/omap_drv.c | 1 + drivers/gpu/drm/qxl/qxl_drv.c | 1 + drivers/gpu/drm/radeon/radeon_drv.c | 1 + drivers/gpu/drm/rcar-du/rcar_du_drv.c | 1 + drivers/gpu/drm/rockchip/rockchip_drm_drv.c | 1 + drivers/gpu/drm/shmobile/shmob_drm_drv.c | 1 + drivers/gpu/drm/sti/sti_drv.c | 1 + drivers/gpu/drm/tegra/drm.c | 1 + drivers/gpu/drm/udl/udl_drv.c | 1 + drivers/gpu/drm/vmwgfx/vmwgfx_drv.c | 1 + include/drm/drmP.h | 8 ++ include/drm/drm_crtc.h | 4 + include/uapi/drm/drm.h | 10 ++ 24 files changed, 303 insertions(+), 42 deletions(-) -- 1.9.1 _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx http://lists.freedesktop.org/mailman/listinfo/dri-devel
