[PATCH 8/9] drm/syncobj: add timeline signal ioctl for syncobj v5
Lionel Landwerlin
lionel.g.landwerlin at intel.com
Sat Mar 30 14:05:24 UTC 2019
On 28/03/2019 13:33, Lionel Landwerlin wrote:
> On 28/03/2019 13:08, Chunming Zhou wrote:
>> 在 2019/3/28 20:53, Lionel Landwerlin 写道:
>>> On 25/03/2019 08:32, Chunming Zhou wrote:
>>>> v2: individually allocate chain array, since chain node is free
>>>> independently.
>>>> v3: all existing points must be already signaled before cpu perform
>>>> signal operation,
>>>> so add check condition for that.
>>>> v4: remove v3 change and add checking to prevent out-of-order
>>>> v5: unify binary and timeline
>>>>
>>>> Signed-off-by: Chunming Zhou <david1.zhou at amd.com>
>>>> Cc: Tobias Hector <Tobias.Hector at amd.com>
>>>> Cc: Jason Ekstrand <jason at jlekstrand.net>
>>>> Cc: Dave Airlie <airlied at redhat.com>
>>>> Cc: Chris Wilson <chris at chris-wilson.co.uk>
>>>> Cc: Lionel Landwerlin <lionel.g.landwerlin at intel.com>
>>>> ---
>>>> drivers/gpu/drm/drm_internal.h | 2 +
>>>> drivers/gpu/drm/drm_ioctl.c | 2 +
>>>> drivers/gpu/drm/drm_syncobj.c | 73
>>>> ++++++++++++++++++++++++++++++++++
>>>> include/uapi/drm/drm.h | 1 +
>>>> 4 files changed, 78 insertions(+)
>>>>
>>>> diff --git a/drivers/gpu/drm/drm_internal.h
>>>> b/drivers/gpu/drm/drm_internal.h
>>>> index dd11ae5f1eef..d9a483a5fce0 100644
>>>> --- a/drivers/gpu/drm/drm_internal.h
>>>> +++ b/drivers/gpu/drm/drm_internal.h
>>>> @@ -190,6 +190,8 @@ int drm_syncobj_reset_ioctl(struct drm_device
>>>> *dev, void *data,
>>>> struct drm_file *file_private);
>>>> int drm_syncobj_signal_ioctl(struct drm_device *dev, void *data,
>>>> struct drm_file *file_private);
>>>> +int drm_syncobj_timeline_signal_ioctl(struct drm_device *dev, void
>>>> *data,
>>>> + struct drm_file *file_private);
>>>> int drm_syncobj_query_ioctl(struct drm_device *dev, void *data,
>>>> struct drm_file *file_private);
>>>> diff --git a/drivers/gpu/drm/drm_ioctl.c
>>>> b/drivers/gpu/drm/drm_ioctl.c
>>>> index 92b3b7b2fd81..d337f161909c 100644
>>>> --- a/drivers/gpu/drm/drm_ioctl.c
>>>> +++ b/drivers/gpu/drm/drm_ioctl.c
>>>> @@ -696,6 +696,8 @@ static const struct drm_ioctl_desc drm_ioctls[]
>>>> = {
>>>> DRM_UNLOCKED|DRM_RENDER_ALLOW),
>>>> DRM_IOCTL_DEF(DRM_IOCTL_SYNCOBJ_SIGNAL,
>>>> drm_syncobj_signal_ioctl,
>>>> DRM_UNLOCKED|DRM_RENDER_ALLOW),
>>>> + DRM_IOCTL_DEF(DRM_IOCTL_SYNCOBJ_TIMELINE_SIGNAL,
>>>> drm_syncobj_timeline_signal_ioctl,
>>>> + DRM_UNLOCKED|DRM_RENDER_ALLOW),
>>>> DRM_IOCTL_DEF(DRM_IOCTL_SYNCOBJ_QUERY, drm_syncobj_query_ioctl,
>>>> DRM_UNLOCKED|DRM_RENDER_ALLOW),
>>>> DRM_IOCTL_DEF(DRM_IOCTL_CRTC_GET_SEQUENCE,
>>>> drm_crtc_get_sequence_ioctl, DRM_UNLOCKED),
>>>> diff --git a/drivers/gpu/drm/drm_syncobj.c
>>>> b/drivers/gpu/drm/drm_syncobj.c
>>>> index ee2d66e047e7..099596190845 100644
>>>> --- a/drivers/gpu/drm/drm_syncobj.c
>>>> +++ b/drivers/gpu/drm/drm_syncobj.c
>>>> @@ -1183,6 +1183,79 @@ drm_syncobj_signal_ioctl(struct drm_device
>>>> *dev, void *data,
>>>> return ret;
>>>> }
>>>> +int
>>>> +drm_syncobj_timeline_signal_ioctl(struct drm_device *dev, void *data,
>>>> + struct drm_file *file_private)
>>>> +{
>>>> + struct drm_syncobj_timeline_array *args = data;
>>>> + struct drm_syncobj **syncobjs;
>>>> + struct dma_fence_chain **chains;
>>>> + uint64_t *points;
>>>> + uint32_t i, j;
>>>> + int ret;
>>>> +
>>>> + if (!drm_core_check_feature(dev, DRIVER_SYNCOBJ))
>>>> + return -EOPNOTSUPP;
>>>> +
>>>> + if (args->pad != 0)
>>>> + return -EINVAL;
>>>> +
>>>> + if (args->count_handles == 0)
>>>> + return -EINVAL;
>>>> +
>>>> + ret = drm_syncobj_array_find(file_private,
>>>> + u64_to_user_ptr(args->handles),
>>>> + args->count_handles,
>>>> + &syncobjs);
>>>> + if (ret < 0)
>>>> + return ret;
>>>> +
>>>> + points = kmalloc_array(args->count_handles, sizeof(*points),
>>>> + GFP_KERNEL);
>>>> + if (!points) {
>>>> + ret = -ENOMEM;
>>>> + goto out;
>>>> + }
>>>> + if (!u64_to_user_ptr(args->points)) {
>>>> + memset(points, 0, args->count_handles * sizeof(uint64_t));
>>>> + } else if (copy_from_user(points, u64_to_user_ptr(args->points),
>>>> + sizeof(uint64_t) * args->count_handles)) {
>>>> + ret = -EFAULT;
>>>> + goto err_points;
>>>> + }
>>>> +
>>>> + chains = kmalloc_array(args->count_handles, sizeof(void *),
>>>> GFP_KERNEL);
>>>> + if (!chains) {
>>>> + ret = -ENOMEM;
>>>> + goto err_points;
>>>> + }
>>>> + for (i = 0; i < args->count_handles; i++) {
>>>> + chains[i] = kzalloc(sizeof(struct dma_fence_chain),
>>>> GFP_KERNEL);
>>>> + if (!chains[i]) {
>>>> + for (j = 0; j < i; j++)
>>>> + kfree(chains[j]);
>>>> + ret = -ENOMEM;
>>>> + goto err_chains;
>>>> + }
>>>> + }
>>>> +
>>>> + for (i = 0; i < args->count_handles; i++) {
>>>> + struct dma_fence *fence = dma_fence_get_stub();
>>>> +
>>>> + drm_syncobj_add_point(syncobjs[i], chains[i],
>>>> + fence, points[i]);
>>>> + dma_fence_put(fence);
>>>> + }
>>>
>>> I think I found an issue where the implementation doesn't match what
>>> the spec requires on host signaling.
>>>
>>> Consider the following :
>>>
>>>
>>> Timeline semaphore has a value of 4.
>>>
>>> A device submits a commands to signal point 5.
>>>
>>> The host signals point 6.
>>>
>>>
>>> The value of the timeline will remain 4 until the device commands
>>> complete, at which point it will change to 6.
>>>
>>> But the specification seems to say that the timeline value should be 6
>>> once the host signaling completes.
>>>
>>>
>>> The only option that I see working would be to add point 6 in the
>>> timeline and wait on that point to complete.
>>>
>>>
>>> Christian, David, what do you think?
>> This is exactly what I said before, see V3 comment in the patch head.
>>
>> But Jeson said this should be guranteed by user and application.
>>
>> Btw, if we wait all previous points completion this ioctl could be
>> blocked.
>>
>>
>> -David
>
>
> I haven't seen anything that explicitly forbids that in the spec.
>
> Trying to get a clarification.
>
>
> -Lionel
So it looks like this won't be allowed by the vulkan spec.
Sorry, I genuinely thought this was allowed because we can end up in
such situation on the device side :(
Not quite sure how useful it would be to have some checks here as most
of the error handling can only be done within the add_point() function
and requires taking the syncobj lock.
As much as I could like to see more error checking, I guess this isn't
doable without more locking.
-Lionel
>
>
>>
>>
>>>
>>> Thanks,
>>>
>>>
>>> -Lionel
>>>
>>>
>>>> +err_chains:
>>>> + kfree(chains);
>>>> +err_points:
>>>> + kfree(points);
>>>> +out:
>>>> + drm_syncobj_array_free(syncobjs, args->count_handles);
>>>> +
>>>> + return ret;
>>>> +}
>>>> +
>>>> int drm_syncobj_query_ioctl(struct drm_device *dev, void *data,
>>>> struct drm_file *file_private)
>>>> {
>>>> diff --git a/include/uapi/drm/drm.h b/include/uapi/drm/drm.h
>>>> index e8d0d6b51875..236b01a1fabf 100644
>>>> --- a/include/uapi/drm/drm.h
>>>> +++ b/include/uapi/drm/drm.h
>>>> @@ -943,6 +943,7 @@ extern "C" {
>>>> #define DRM_IOCTL_SYNCOBJ_TIMELINE_WAIT DRM_IOWR(0xCA, struct
>>>> drm_syncobj_timeline_wait)
>>>> #define DRM_IOCTL_SYNCOBJ_QUERY DRM_IOWR(0xCB, struct
>>>> drm_syncobj_timeline_array)
>>>> #define DRM_IOCTL_SYNCOBJ_TRANSFER DRM_IOWR(0xCC, struct
>>>> drm_syncobj_transfer)
>>>> +#define DRM_IOCTL_SYNCOBJ_TIMELINE_SIGNAL DRM_IOWR(0xCD, struct
>>>> drm_syncobj_timeline_array)
>>>> /**
>>>> * Device specific ioctls should only be in their respective
>>>> headers
>>>
>
> _______________________________________________
> dri-devel mailing list
> dri-devel at lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/dri-devel
More information about the amd-gfx
mailing list