Hi Brian,
On Fri, Feb 22, 2019 at 02:04:10PM +0000, Brian Starkey wrote:
On Thu, Feb 21, 2019 at 12:31:53PM +0200, Laurent Pinchart wrote:
Hello everybody,
This patch series implements display writeback support for the R-Car Gen3 platforms in the VSP1 and DU drivers.
Patches 01/19 to 11/19 prepare the VSP1 driver for writeback support with all the necessary plumbing, including extensions of the API between the VSP1 and DU drivers.
Compared to v4 the major change is the move from V4L2 to DRM writeback connectors for the userspace API. This has caused a few issues with writeback support to be uncovered, and they are addressed by patches 12/19 to 14/19. Patch 15/19 is an unrelated drive-by fix.
Patches 16/19 to 18/19 then perform refactoring of the DU driver, to finally add writeback support in patch 19/19.
The writeback pixel format is restricted to RGB, due to the VSP1 outputting RGB to the display and lacking a separate colour space conversion unit for writeback. The resolution can be freely picked by will result in cropping or composing, not scaling.
I think this sentence about cropping doesn't match the implementation, as you're checking the framebuffer size against the mode.
That's true, it was different when using V4L2, but now the resolution is fixed.
We want to enable scaling/composing on writeback (which our HW can do). I thought we'd add WRITEBACK_X/Y/W/H properties to set the destination buffer coordinates. One of our team is working on that now.
We don't have cropping, but I thought that could be achieved by exposing CRTC_X/Y/W/H on writeback connectors.
I don't have a use case from cropping or composing writeback at the moment, but such an API would likely work.
Writeback requests are queued to the hardware on page flip (atomic flush), and complete at the next vblank. This means that a queued writeback buffer will not be processed until the next page flip, but once it starts being written to by the VSP, it will complete at the next vblank regardless of whether another page flip occurs at that time.
The code is based on a merge of the media master branch, the drm-next branch and the R-Car DT next branch. For convenience patches can be found at
git://linuxtv.org/pinchartl/media.git v4l2/vsp1/writebackKieran Bingham (1): Revert "[media] v4l: vsp1: Supply frames to the DU continuously"
Laurent Pinchart (18): media: vsp1: wpf: Fix partition configuration for display pipelines media: vsp1: Replace leftover occurrence of fragment with body media: vsp1: Fix addresses of display-related registers for VSP-DL media: vsp1: Refactor vsp1_video_complete_buffer() for later reuse media: vsp1: Replace the display list internal flag with a flags field media: vsp1: dl: Support one-shot entries in the display list media: vsp1: wpf: Add writeback support media: vsp1: drm: Split RPF format setting to separate function media: vsp1: drm: Extend frame completion API to the DU driver media: vsp1: drm: Implement writeback support drm: writeback: Cleanup job ownership handling when queuing job drm: writeback: Fix leak of writeback job drm: writeback: Add job prepare and cleanup operations drm/msm: Remove prototypes for non-existing functions drm: rcar-du: Fix rcar_du_crtc structure documentation drm: rcar-du: Store V4L2 fourcc in rcar_du_format_info structure drm: rcar-du: vsp: Extract framebuffer (un)mapping to separate functions drm: rcar-du: Add writeback support for R-Car Gen3
drivers/gpu/drm/arm/malidp_mw.c | 3 +- drivers/gpu/drm/drm_atomic_helper.c | 11 ++ drivers/gpu/drm/drm_atomic_state_helper.c | 4 + drivers/gpu/drm/drm_atomic_uapi.c | 31 +-- drivers/gpu/drm/drm_writeback.c | 71 ++++++- drivers/gpu/drm/msm/msm_drv.h | 2 - drivers/gpu/drm/rcar-du/Kconfig | 4 + drivers/gpu/drm/rcar-du/Makefile | 3 +- drivers/gpu/drm/rcar-du/rcar_du_crtc.h | 9 +- drivers/gpu/drm/rcar-du/rcar_du_kms.c | 37 ++++ drivers/gpu/drm/rcar-du/rcar_du_kms.h | 1 + drivers/gpu/drm/rcar-du/rcar_du_vsp.c | 121 ++++++------ drivers/gpu/drm/rcar-du/rcar_du_vsp.h | 17 ++ drivers/gpu/drm/rcar-du/rcar_du_writeback.c | 203 ++++++++++++++++++++ drivers/gpu/drm/rcar-du/rcar_du_writeback.h | 39 ++++ drivers/gpu/drm/vc4/vc4_txp.c | 2 +- drivers/media/platform/vsp1/vsp1_dl.c | 127 ++++++++++-- drivers/media/platform/vsp1/vsp1_dl.h | 8 +- drivers/media/platform/vsp1/vsp1_drm.c | 92 ++++++--- drivers/media/platform/vsp1/vsp1_drm.h | 2 +- drivers/media/platform/vsp1/vsp1_drv.c | 15 ++ drivers/media/platform/vsp1/vsp1_pipe.c | 5 + drivers/media/platform/vsp1/vsp1_pipe.h | 1 + drivers/media/platform/vsp1/vsp1_regs.h | 6 +- drivers/media/platform/vsp1/vsp1_rwpf.h | 2 + drivers/media/platform/vsp1/vsp1_video.c | 49 +++-- drivers/media/platform/vsp1/vsp1_wpf.c | 68 +++++-- include/drm/drm_modeset_helper_vtables.h | 7 + include/drm/drm_writeback.h | 30 ++- include/media/vsp1.h | 19 +- 30 files changed, 790 insertions(+), 199 deletions(-) create mode 100644 drivers/gpu/drm/rcar-du/rcar_du_writeback.c create mode 100644 drivers/gpu/drm/rcar-du/rcar_du_writeback.h