Re: [PATCH] drm/msm: Add MSM_SUBMIT_BO_NO_IMPLICIT
From: Daniel Vetter
Date: Thu Jan 05 2023 - 07:50:04 EST
On Tue, Dec 06, 2022 at 11:21:23AM -0800, Rob Clark wrote:
> From: Rob Clark <robdclark@xxxxxxxxxxxx>
>
> In cases where implicit sync is used, it is still useful (for things
> like sub-allocation, etc) to allow userspace to opt-out of implicit
> sync on per-BO basis.
>
> Signed-off-by: Rob Clark <robdclark@xxxxxxxxxxxx>
> ---
> drivers/gpu/drm/msm/msm_drv.c | 3 ++-
> drivers/gpu/drm/msm/msm_gem_submit.c | 11 +++++++++++
> include/uapi/drm/msm_drm.h | 4 +++-
> 3 files changed, 16 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/gpu/drm/msm/msm_drv.c b/drivers/gpu/drm/msm/msm_drv.c
> index 017a512982a2..e0e1199a822f 100644
> --- a/drivers/gpu/drm/msm/msm_drv.c
> +++ b/drivers/gpu/drm/msm/msm_drv.c
> @@ -45,9 +45,10 @@
> * - 1.7.0 - Add MSM_PARAM_SUSPENDS to access suspend count
> * - 1.8.0 - Add MSM_BO_CACHED_COHERENT for supported GPUs (a6xx)
> * - 1.9.0 - Add MSM_SUBMIT_FENCE_SN_IN
> + * - 1.10.0 - Add MSM_SUBMIT_BO_NO_IMPLICIT
> */
> #define MSM_VERSION_MAJOR 1
> -#define MSM_VERSION_MINOR 9
> +#define MSM_VERSION_MINOR 10
> #define MSM_VERSION_PATCHLEVEL 0
>
> static const struct drm_mode_config_funcs mode_config_funcs = {
> diff --git a/drivers/gpu/drm/msm/msm_gem_submit.c b/drivers/gpu/drm/msm/msm_gem_submit.c
> index eb3536e3d66a..8bad07a04f85 100644
> --- a/drivers/gpu/drm/msm/msm_gem_submit.c
> +++ b/drivers/gpu/drm/msm/msm_gem_submit.c
> @@ -334,9 +334,20 @@ static int submit_fence_sync(struct msm_gem_submit *submit, bool no_implicit)
> if (ret)
> return ret;
>
> + /* If userspace has determined that explicit fencing is
> + * used, it can disable implicit sync on the entire
> + * submit:
> + */
> if (no_implicit)
> continue;
>
> + /* Otherwise userspace can ask for implicit sync to be
> + * disabled on specific buffers. This is useful for internal
> + * usermode driver managed buffers, suballocation, etc.
> + */
> + if (submit->bos[i].flags & MSM_SUBMIT_BO_NO_IMPLICIT)
> + continue;
> +
> ret = drm_sched_job_add_implicit_dependencies(&submit->base,
Won't this break shrinkers and fun stuff like that? It's why we added the
new USAGE_OTHER fence slot at least, and also why I wonder whether we
shouldn't push this into the helper to make the right call. Every driver
kinda needs the same wheel.
-Daniel
> obj,
> write);
> diff --git a/include/uapi/drm/msm_drm.h b/include/uapi/drm/msm_drm.h
> index f54b48ef6a2d..329100016e7c 100644
> --- a/include/uapi/drm/msm_drm.h
> +++ b/include/uapi/drm/msm_drm.h
> @@ -222,10 +222,12 @@ struct drm_msm_gem_submit_cmd {
> #define MSM_SUBMIT_BO_READ 0x0001
> #define MSM_SUBMIT_BO_WRITE 0x0002
> #define MSM_SUBMIT_BO_DUMP 0x0004
> +#define MSM_SUBMIT_BO_NO_IMPLICIT 0x0008
>
> #define MSM_SUBMIT_BO_FLAGS (MSM_SUBMIT_BO_READ | \
> MSM_SUBMIT_BO_WRITE | \
> - MSM_SUBMIT_BO_DUMP)
> + MSM_SUBMIT_BO_DUMP | \
> + MSM_SUBMIT_BO_NO_IMPLICIT)
>
> struct drm_msm_gem_submit_bo {
> __u32 flags; /* in, mask of MSM_SUBMIT_BO_x */
> --
> 2.38.1
>
--
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch