Sometimes, all the user wants to do is add a synchronization point. Userspace can already do that by submitting a NULL job, but this implies submitting something to the GPU when we could simply skip the job and signal the done fence directly.
v5: * New patch
Signed-off-by: Boris Brezillon boris.brezillon@collabora.com --- drivers/gpu/drm/panfrost/panfrost_drv.c | 9 +++++++-- drivers/gpu/drm/panfrost/panfrost_job.c | 6 ++++++ include/uapi/drm/panfrost_drm.h | 7 +++++++ 3 files changed, 20 insertions(+), 2 deletions(-)
diff --git a/drivers/gpu/drm/panfrost/panfrost_drv.c b/drivers/gpu/drm/panfrost/panfrost_drv.c index 30dc158d56e6..89a0c484310c 100644 --- a/drivers/gpu/drm/panfrost/panfrost_drv.c +++ b/drivers/gpu/drm/panfrost/panfrost_drv.c @@ -542,7 +542,9 @@ static const struct panfrost_submit_ioctl_version_info submit_versions[] = { [1] = { 48, 8, 16 }, };
-#define PANFROST_JD_ALLOWED_REQS PANFROST_JD_REQ_FS +#define PANFROST_JD_ALLOWED_REQS \ + (PANFROST_JD_REQ_FS | \ + PANFROST_JD_REQ_DEP_ONLY)
static int panfrost_submit_job(struct drm_device *dev, struct drm_file *file_priv, @@ -559,7 +561,10 @@ panfrost_submit_job(struct drm_device *dev, struct drm_file *file_priv, if (args->requirements & ~PANFROST_JD_ALLOWED_REQS) return -EINVAL;
- if (!args->head) + /* If this is a dependency-only job, the job chain head should be NULL, + * otherwise it should be non-NULL. + */ + if ((args->head != 0) != !(args->requirements & PANFROST_JD_REQ_DEP_ONLY)) return -EINVAL;
bo_stride = submit_versions[version].bo_ref_stride; diff --git a/drivers/gpu/drm/panfrost/panfrost_job.c b/drivers/gpu/drm/panfrost/panfrost_job.c index 0367cee8f6df..6d8706d4a096 100644 --- a/drivers/gpu/drm/panfrost/panfrost_job.c +++ b/drivers/gpu/drm/panfrost/panfrost_job.c @@ -192,6 +192,12 @@ static void panfrost_job_hw_submit(struct panfrost_job *job, int js) u64 jc_head = job->jc; int ret;
+ if (job->requirements & PANFROST_JD_REQ_DEP_ONLY) { + /* Nothing to execute, signal the fence directly. */ + dma_fence_signal_locked(job->done_fence); + return; + } + panfrost_devfreq_record_busy(&pfdev->pfdevfreq);
ret = pm_runtime_get_sync(pfdev->dev); diff --git a/include/uapi/drm/panfrost_drm.h b/include/uapi/drm/panfrost_drm.h index 5e3f8a344f41..b9df066970f6 100644 --- a/include/uapi/drm/panfrost_drm.h +++ b/include/uapi/drm/panfrost_drm.h @@ -46,6 +46,13 @@ extern "C" { #define DRM_IOCTL_PANFROST_PERFCNT_DUMP DRM_IOW(DRM_COMMAND_BASE + DRM_PANFROST_PERFCNT_DUMP, struct drm_panfrost_perfcnt_dump)
#define PANFROST_JD_REQ_FS (1 << 0) + +/* + * Dependency only job. The job chain head should be set to 0 when this flag + * is set. + */ +#define PANFROST_JD_REQ_DEP_ONLY (1 << 1) + /** * struct drm_panfrost_submit - ioctl argument for submitting commands to the 3D * engine.