On 06/30/17 14:04, Mauro Carvalho Chehab wrote:
> Em Fri, 16 Jun 2017 16:39:10 +0900
> Gustavo Padovan <gustavo@xxxxxxxxxxx> escreveu:
>
>> From: Gustavo Padovan <gustavo.padovan@xxxxxxxxxxxxx>
>>
>> Implement the needed pieces to let userspace subscribe for
>> V4L2_EVENT_BUF_QUEUED events. Videobuf2 will queue the event for the
>> DQEVENT ioctl.
>>
>> Signed-off-by: Gustavo Padovan <gustavo.padovan@xxxxxxxxxxxxx>
>> ---
>> drivers/media/v4l2-core/v4l2-ctrls.c | 6 +++++-
>> drivers/media/v4l2-core/videobuf2-core.c | 15 +++++++++++++++
>> 2 files changed, 20 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/media/v4l2-core/v4l2-ctrls.c b/drivers/media/v4l2-core/v4l2-ctrls.c
>> index 5aed7bd..f55b5da 100644
>> --- a/drivers/media/v4l2-core/v4l2-ctrls.c
>> +++ b/drivers/media/v4l2-core/v4l2-ctrls.c
>> @@ -3435,8 +3435,12 @@ EXPORT_SYMBOL(v4l2_ctrl_log_status);
>> int v4l2_ctrl_subscribe_event(struct v4l2_fh *fh,
>> const struct v4l2_event_subscription *sub)
>> {
>> - if (sub->type == V4L2_EVENT_CTRL)
>> + switch (sub->type) {
>> + case V4L2_EVENT_CTRL:
>> return v4l2_event_subscribe(fh, sub, 0, &v4l2_ctrl_sub_ev_ops);
>> + case V4L2_EVENT_BUF_QUEUED:
>> + return v4l2_event_subscribe(fh, sub, 0, NULL);
>> + }
>> return -EINVAL;
>> }
>> EXPORT_SYMBOL(v4l2_ctrl_subscribe_event);
>> diff --git a/drivers/media/v4l2-core/videobuf2-core.c b/drivers/media/v4l2-core/videobuf2-core.c
>> index 29aa9d4..00d9c35 100644
>> --- a/drivers/media/v4l2-core/videobuf2-core.c
>> +++ b/drivers/media/v4l2-core/videobuf2-core.c
>> @@ -25,6 +25,7 @@
>> #include <linux/kthread.h>
>>
>> #include <media/videobuf2-core.h>
>> +#include <media/v4l2-event.h>
>> #include <media/v4l2-mc.h>
>>
>> #include <trace/events/vb2.h>
>> @@ -1221,6 +1222,18 @@ static int __prepare_dmabuf(struct vb2_buffer *vb, const void *pb)
>> return ret;
>> }
>>
>> +static void vb2_buffer_queued_event(struct vb2_buffer *vb)
>> +{
>> + struct video_device *vdev = to_video_device(vb->vb2_queue->dev);
>> + struct v4l2_event event;
>> +
>> + memset(&event, 0, sizeof(event));
>> + event.type = V4L2_EVENT_BUF_QUEUED;
>> + event.u.buf_queued.index = vb->index;
>> +
>> + v4l2_event_queue(vdev, &event);
>> +}
>> +
>
> It doesn't sound right to add a V4L2 event to VB2 core. The hole point
> of splitting the core from V4L2 specific stuff is to allow VB2 to be
> used by non-V4L2 APIs[1]. Please move this to videobuf2-v4l2.
Good point. So this should be a callback to the higher level.
One thing I was wondering about: v4l2_event_queue sends the event to all
open filehandles of the video node that subscribed to this event. Is that
what we want? Or should we use v4l2_event_queue_fh to only send it to the
vb2 queue owner? I don't know what is best. I think it is OK to send it
to anyone that is interested. If nothing else it will help debugging.
Regards,
Hans
>
> [1] The split happened as part of a patchset meant to make the DVB
> core to use VB2 and provide DMA APIs to it. Unfortunately, the
> developer that worked on this project moved to some other project.
> The final patch was not applied yet. I have it on my patchwork
> queue. I intend to test and apply it sometime this year.
>
>
>
>> /**
>> * __enqueue_in_driver() - enqueue a vb2_buffer in driver for processing
>> */
>> @@ -1234,6 +1247,8 @@ static void __enqueue_in_driver(struct vb2_buffer *vb)
>> trace_vb2_buf_queue(q, vb);
>>
>> call_void_vb_qop(vb, buf_queue, vb);
>> +
>> + vb2_buffer_queued_event(vb);
>> }
>>
>> static int __buf_prepare(struct vb2_buffer *vb, const void *pb)
>
>
