lkml.org 
[lkml]   [2018]   [Nov]   [2]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
SubjectRe: [PATCH 2/5] drm/virtio: add uapi for in and out explicit fences
From
Date
Hey Emil,

On 2018-11-02 14:34, Emil Velikov wrote:
> On Thu, 1 Nov 2018 at 12:56, Robert Foss <robert.foss@collabora.com> wrote:
>> On 2018-10-31 10:38, Emil Velikov wrote:
>>> Hi Rob,
>>>
>>> On Thu, 25 Oct 2018 at 19:38, Robert Foss <robert.foss@collabora.com> wrote:
>>>>
>>>> Add a new field called fence_fd that will be used by userspace to send
>>>> in-fences to the kernel and receive out-fences created by the kernel.
>>>>
>>>> This uapi enables virtio to take advantage of explicit synchronization of
>>>> dma-bufs.
>>>>
>>>> There are two new flags:
>>>>
>>>> * VIRTGPU_EXECBUF_FENCE_FD_IN to be used when passing an in-fence fd.
>>>> * VIRTGPU_EXECBUF_FENCE_FD_OUT to be used when requesting an out-fence fd
>>>>
>>>> The execbuffer IOCTL is now read-write to allow the userspace to read the
>>>> out-fence.
>>>>
>>>> On error -1 should be returned in the fence_fd field.
>>>>
>>>> Signed-off-by: Gustavo Padovan <gustavo.padovan@collabora.com>
>>>> Signed-off-by: Robert Foss <robert.foss@collabora.com>
>>>> ---
>>>> Changes since v2:
>>>> - Since exbuf-flags is a new flag, check that unsupported
>>>> flags aren't set.
>>>>
>>>> drivers/gpu/drm/virtio/virtgpu_ioctl.c | 5 +++++
>>>> include/uapi/drm/virtgpu_drm.h | 13 ++++++++++---
>>>> 2 files changed, 15 insertions(+), 3 deletions(-)
>>>>
>>>> diff --git a/drivers/gpu/drm/virtio/virtgpu_ioctl.c b/drivers/gpu/drm/virtio/virtgpu_ioctl.c
>>>> index d01a9ed100d1..1af289b28fc4 100644
>>>> --- a/drivers/gpu/drm/virtio/virtgpu_ioctl.c
>>>> +++ b/drivers/gpu/drm/virtio/virtgpu_ioctl.c
>>>> @@ -116,9 +116,14 @@ static int virtio_gpu_execbuffer_ioctl(struct drm_device *dev, void *data,
>>>> struct ww_acquire_ctx ticket;
>>>> void *buf;
>>>>
>>>> + exbuf->fence_fd = -1;
>>>> +
>>> Move this after the sanity checking.
>>
>> Agreed. Fixed in v4
>>
>>>
>>>> if (vgdev->has_virgl_3d == false)
>>>> return -ENOSYS;
>>>>
>>>> + if ((exbuf->flags & ~VIRTGPU_EXECBUF_FLAGS))
>>>> + return -EINVAL;
>>>> +
>>> I assume this did this trigger when using old userspace?
>>
>> No, not as far as I'm aware. This check is there to prevent userspace from
>> polluting the bitspace of flag, so that all free bits can be used for new flags.
>>
>> As far as I understand this is pointed out by a drm driver development document
>> written by danvet, which I unfortunately can't seem to find the link for at the
>> moment.
>>
> Yes that is correct. What I was asking is:
>
> Does a kernel with this patch, work with mesa lacking the corresponding updates?
> I'd imagine things work just fine.

Yes it does!

>
> -Emil
> _______________________________________________
> dri-devel mailing list
> dri-devel@lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/dri-devel
>

\
 
 \ /
  Last update: 2018-11-02 15:43    [W:0.067 / U:1.108 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site