Am Dienstag, den 05.06.2018, 12:03 -0700 schrieb Eric Anholt:

Since our seqno value comes from a counter associated with the GPU ring, not the entity (aka client), they'll be completed out of order. There's actually no need for this code at all, since we don't have enable_signaling() and thus DMA_FENCE_SIGNALED_BIT will be set before we could be called.

Signed-off-by: Eric Anholt eric@anholt.net

Reviewed-by: Lucas Stach l.stach@pengutronix.de

---

drivers/gpu/drm/v3d/v3d_drv.h   |  1 -  drivers/gpu/drm/v3d/v3d_fence.c | 13 ++++---------  drivers/gpu/drm/v3d/v3d_gem.c   |  7 ++-----  drivers/gpu/drm/v3d/v3d_irq.c   |  3 ---  4 files changed, 6 insertions(+), 18 deletions(-)

diff --git a/drivers/gpu/drm/v3d/v3d_drv.h b/drivers/gpu/drm/v3d/v3d_drv.h index 26005abd9c5d..f32ac8c98f37 100644 --- a/drivers/gpu/drm/v3d/v3d_drv.h +++ b/drivers/gpu/drm/v3d/v3d_drv.h @@ -25,7 +25,6 @@ struct v3d_queue_state {     u64 fence_context;   u64 emit_seqno;

• u64 finished_seqno;

};    struct v3d_dev { diff --git a/drivers/gpu/drm/v3d/v3d_fence.c b/drivers/gpu/drm/v3d/v3d_fence.c index 087d49c8cb12..bfe31a89668b 100644 --- a/drivers/gpu/drm/v3d/v3d_fence.c +++ b/drivers/gpu/drm/v3d/v3d_fence.c @@ -40,19 +40,14 @@ static bool v3d_fence_enable_signaling(struct dma_fence *fence)   return true;  }   -static bool v3d_fence_signaled(struct dma_fence *fence) -{

• struct v3d_fence *f = to_v3d_fence(fence);
• struct v3d_dev *v3d = to_v3d_dev(f->dev);
• return v3d->queue[f->queue].finished_seqno >= f->seqno;

-}

const struct dma_fence_ops v3d_fence_ops = {   .get_driver_name = v3d_fence_get_driver_name,   .get_timeline_name = v3d_fence_get_timeline_name,   .enable_signaling = v3d_fence_enable_signaling,

• .signaled = v3d_fence_signaled,

• /* Each of our fences gets signaled as complete by the IRQ
• * handler, so we rely on the core's tracking of signaling.
• */
• .signaled = NULL,

.wait = dma_fence_default_wait,   .release = dma_fence_free,  }; diff --git a/drivers/gpu/drm/v3d/v3d_gem.c b/drivers/gpu/drm/v3d/v3d_gem.c index 9ea83bdb9a30..d06d6697e089 100644 --- a/drivers/gpu/drm/v3d/v3d_gem.c +++ b/drivers/gpu/drm/v3d/v3d_gem.c @@ -657,17 +657,14 @@ void  v3d_gem_destroy(struct drm_device *dev)  {   struct v3d_dev *v3d = to_v3d_dev(dev);

• enum v3d_queue q;

v3d_sched_fini(v3d);     /* Waiting for exec to finish would need to be done before    * unregistering V3D.    */

• for (q = 0; q < V3D_MAX_QUEUES; q++) {

• WARN_ON(v3d->queue[q].emit_seqno !=
  

• 	v3d->queue[q].finished_seqno);
  

• }

• WARN_ON(v3d->bin_job);
• WARN_ON(v3d->render_job);

drm_mm_takedown(&v3d->mm);   diff --git a/drivers/gpu/drm/v3d/v3d_irq.c b/drivers/gpu/drm/v3d/v3d_irq.c index 77e1fa046c10..e07514eb11b5 100644 --- a/drivers/gpu/drm/v3d/v3d_irq.c +++ b/drivers/gpu/drm/v3d/v3d_irq.c @@ -87,15 +87,12 @@ v3d_irq(int irq, void *arg)   }     if (intsts & V3D_INT_FLDONE) {

• v3d->queue[V3D_BIN].finished_seqno++;
  

dma_fence_signal(v3d->bin_job->bin.done_fence);   status = IRQ_HANDLED;   }     if (intsts & V3D_INT_FRDONE) {

• v3d->queue[V3D_RENDER].finished_seqno++;
  

dma_fence_signal(v3d->render_job-

...

render.done_fence);

status = IRQ_HANDLED;   }

Am Dienstag, den 05.06.2018, 12:03 -0700 schrieb Eric Anholt:

This isn't the first time I've had to argue to myself why the '++' was safe.

And now you need to do the same thing with me...

Signed-off-by: Eric Anholt eric@anholt.net

drivers/gpu/drm/v3d/v3d_fence.c | 3 +++  1 file changed, 3 insertions(+)

diff --git a/drivers/gpu/drm/v3d/v3d_fence.c b/drivers/gpu/drm/v3d/v3d_fence.c index bfe31a89668b..6265e9ab4a13 100644 --- a/drivers/gpu/drm/v3d/v3d_fence.c +++ b/drivers/gpu/drm/v3d/v3d_fence.c @@ -3,6 +3,9 @@    #include "v3d_drv.h"   +/* Note that V3D fences are created during v3d_job_run(), so we're

• • already implictly locked.
• */

I don't see where you would be locked in the job_run path. I think what you mean is that this path needs no locks, as it is driven by a single scheduler thread, right?

Regards, Lucas

Between creation and queueing of a job, you need to prevent any other job from being created and queued. Otherwise the scheduler's fences may be signaled out of seqno order.

v2: move mutex unlock to the error label.

Signed-off-by: Eric Anholt eric@anholt.net Fixes: 57692c94dcbe ("drm/v3d: Introduce a new DRM driver for Broadcom V3D V3.x+") --- drivers/gpu/drm/v3d/v3d_drv.h | 5 +++++ drivers/gpu/drm/v3d/v3d_gem.c | 4 ++++ 2 files changed, 9 insertions(+)

diff --git a/drivers/gpu/drm/v3d/v3d_drv.h b/drivers/gpu/drm/v3d/v3d_drv.h index a043ac3aae98..26005abd9c5d 100644 --- a/drivers/gpu/drm/v3d/v3d_drv.h +++ b/drivers/gpu/drm/v3d/v3d_drv.h @@ -85,6 +85,11 @@ struct v3d_dev { */ struct mutex reset_lock;

+ /* Lock taken when creating and pushing the GPU scheduler + * jobs, to keep the sched-fence seqnos in order. + */ + struct mutex sched_lock; + struct { u32 num_allocated; u32 pages_allocated; diff --git a/drivers/gpu/drm/v3d/v3d_gem.c b/drivers/gpu/drm/v3d/v3d_gem.c index b513f9189caf..269fe16379c0 100644 --- a/drivers/gpu/drm/v3d/v3d_gem.c +++ b/drivers/gpu/drm/v3d/v3d_gem.c @@ -550,6 +550,7 @@ v3d_submit_cl_ioctl(struct drm_device *dev, void *data, if (ret) goto fail;

+ mutex_lock(&v3d->sched_lock); if (exec->bin.start != exec->bin.end) { ret = drm_sched_job_init(&exec->bin.base, &v3d->queue[V3D_BIN].sched, @@ -576,6 +577,7 @@ v3d_submit_cl_ioctl(struct drm_device *dev, void *data, kref_get(&exec->refcount); /* put by scheduler job completion */ drm_sched_entity_push_job(&exec->render.base, &v3d_priv->sched_entity[V3D_RENDER]); + mutex_unlock(&v3d->sched_lock);

v3d_attach_object_fences(exec);

@@ -594,6 +596,7 @@ v3d_submit_cl_ioctl(struct drm_device *dev, void *data, return 0;

fail_unreserve: + mutex_unlock(&v3d->sched_lock); v3d_unlock_bo_reservations(dev, exec, &acquire_ctx); fail: v3d_exec_put(exec); @@ -615,6 +618,7 @@ v3d_gem_init(struct drm_device *dev) spin_lock_init(&v3d->job_lock); mutex_init(&v3d->bo_lock); mutex_init(&v3d->reset_lock); + mutex_init(&v3d->sched_lock);

/* Note: We don't allocate address 0. Various bits of HW * treat 0 as special, such as the occlusion query counters