On Tue, Sep 17, 2024 at 01:14:19PM +0200, Antonino Maniscalco wrote:
> Some userspace changes are necessary so add a flag for userspace to
> advertise support for preemption when creating the submitqueue.
>
> When this flag is not set preemption will not be allowed in the middle
> of the submitted IBs therefore mantaining compatibility with older
> userspace.
>
> The flag is rejected if preemption is not supported on the target, this
> allows userspace to know whether preemption is supported.
Just curious, what is the motivation behind informing userspace about
preemption support?
-Akhil
>
> Signed-off-by: Antonino Maniscalco <antomani103@xxxxxxxxx>
> Tested-by: Neil Armstrong <neil.armstrong@xxxxxxxxxx> # on SM8650-QRD
> ---
> drivers/gpu/drm/msm/adreno/a6xx_gpu.c | 12 ++++++++----
> drivers/gpu/drm/msm/msm_submitqueue.c | 3 +++
> include/uapi/drm/msm_drm.h | 5 ++++-
> 3 files changed, 15 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/gpu/drm/msm/adreno/a6xx_gpu.c b/drivers/gpu/drm/msm/adreno/a6xx_gpu.c
> index 736f475d696f..edbcb6d229ba 100644
> --- a/drivers/gpu/drm/msm/adreno/a6xx_gpu.c
> +++ b/drivers/gpu/drm/msm/adreno/a6xx_gpu.c
> @@ -430,8 +430,10 @@ static void a7xx_submit(struct msm_gpu *gpu, struct msm_gem_submit *submit)
> OUT_PKT7(ring, CP_SET_MARKER, 1);
> OUT_RING(ring, 0x101); /* IFPC disable */
>
> - OUT_PKT7(ring, CP_SET_MARKER, 1);
> - OUT_RING(ring, 0x00d); /* IB1LIST start */
> + if (submit->queue->flags & MSM_SUBMITQUEUE_ALLOW_PREEMPT) {
> + OUT_PKT7(ring, CP_SET_MARKER, 1);
> + OUT_RING(ring, 0x00d); /* IB1LIST start */
> + }
>
> /* Submit the commands */
> for (i = 0; i < submit->nr_cmds; i++) {
> @@ -462,8 +464,10 @@ static void a7xx_submit(struct msm_gpu *gpu, struct msm_gem_submit *submit)
> update_shadow_rptr(gpu, ring);
> }
>
> - OUT_PKT7(ring, CP_SET_MARKER, 1);
> - OUT_RING(ring, 0x00e); /* IB1LIST end */
> + if (submit->queue->flags & MSM_SUBMITQUEUE_ALLOW_PREEMPT) {
> + OUT_PKT7(ring, CP_SET_MARKER, 1);
> + OUT_RING(ring, 0x00e); /* IB1LIST end */
> + }
>
> get_stats_counter(ring, REG_A7XX_RBBM_PERFCTR_CP(0),
> rbmemptr_stats(ring, index, cpcycles_end));
> diff --git a/drivers/gpu/drm/msm/msm_submitqueue.c b/drivers/gpu/drm/msm/msm_submitqueue.c
> index 0e803125a325..9b3ffca3f3b4 100644
> --- a/drivers/gpu/drm/msm/msm_submitqueue.c
> +++ b/drivers/gpu/drm/msm/msm_submitqueue.c
> @@ -170,6 +170,9 @@ int msm_submitqueue_create(struct drm_device *drm, struct msm_file_private *ctx,
> if (!priv->gpu)
> return -ENODEV;
>
> + if (flags & MSM_SUBMITQUEUE_ALLOW_PREEMPT && priv->gpu->nr_rings == 1)
> + return -EINVAL;
> +
> ret = msm_gpu_convert_priority(priv->gpu, prio, &ring_nr, &sched_prio);
> if (ret)
> return ret;
> diff --git a/include/uapi/drm/msm_drm.h b/include/uapi/drm/msm_drm.h
> index 3fca72f73861..f37858db34e6 100644
> --- a/include/uapi/drm/msm_drm.h
> +++ b/include/uapi/drm/msm_drm.h
> @@ -345,7 +345,10 @@ struct drm_msm_gem_madvise {
> * backwards compatibility as a "default" submitqueue
> */
>
> -#define MSM_SUBMITQUEUE_FLAGS (0)
> +#define MSM_SUBMITQUEUE_ALLOW_PREEMPT 0x00000001
> +#define MSM_SUBMITQUEUE_FLAGS ( \
> + MSM_SUBMITQUEUE_ALLOW_PREEMPT | \
> + 0)
>
> /*
> * The submitqueue priority should be between 0 and MSM_PARAM_PRIORITIES-1,
>
> --
> 2.46.0
>
