Hi, As drm_atomic_helper_commit_planes() calls atomic_flush for CRTCs sequentially and a driver's atomic_flush callback could be blocking, the performance for flushing multiple CRTCs in a single atomic commit could be low, like page flip for multiple CRTCs. A real case is imx8-dc, which supports two CRTCs and does atomic_flush in a blocking way, i.e., waits for a done event for loading shadow registers.
To resolve that, introduce an optional kthread worker to conduct flush in drm_atomic_helper_commit_planes(), so that flush can run in parallel for multiple CRTCs. Drivers should call drmm_crtc_flush_worker_init() to initialize the kthread worker if they want to use it. Patch 1 adds the optional kthread worker support. Patch 2 makes imx8-dc use the kthread worker. Let me know your thoughts. Thanks. Signed-off-by: Liu Ying <[email protected]> --- Liu Ying (2): drm/atomic-helper: Support atomic flush with an optional kthread worker drm/imx: dc-crtc: Use flush worker drivers/gpu/drm/drm_atomic_helper.c | 27 ++++++++++++++++- drivers/gpu/drm/drm_crtc.c | 59 +++++++++++++++++++++++++++++++++++++ drivers/gpu/drm/imx/dc/dc-crtc.c | 9 +++++- include/drm/drm_crtc.h | 45 ++++++++++++++++++++++++++++ 4 files changed, 138 insertions(+), 2 deletions(-) --- base-commit: dcb6fa37fd7bc9c3d2b066329b0d27dedf8becaa change-id: 20251031-drm-crtc-flush-worker-0aac27acf40f Best regards, -- Liu Ying <[email protected]>
