Messages in this thread | | | Date | Wed, 7 Feb 2024 12:22:46 +0100 | Subject | Re: [PATCH v19 0/9] Add DELETE_BUF ioctl | From | Benjamin Gaignard <> |
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Le 07/02/2024 à 12:20, Hans Verkuil a écrit : > On 07/02/2024 12:15, Benjamin Gaignard wrote: >> Le 07/02/2024 à 10:12, Hans Verkuil a écrit : >>> Hi Benjamin, >>> >>> On 06/02/2024 09:58, Hans Verkuil wrote: >>>> On 06/02/2024 09:02, Benjamin Gaignard wrote: >>>>> Unlike when resolution change on keyframes, dynamic resolution change >>>>> on inter frames doesn't allow to do a stream off/on sequence because >>>>> it is need to keep all previous references alive to decode inter frames. >>>>> This constraint have two main problems: >>>>> - more memory consumption. >>>>> - more buffers in use. >>>>> To solve these issue this series introduce DELETE_BUFS ioctl and remove >>>>> the 32 buffers limit per queue. >>>> This v19 looks good. There are three outstanding issues that I need to take a >>>> look at: >>>> >>>> 1) Can we still signal support for DELETE_BUFS in the V4L2_BUF_CAP_ caps? >>>> It would be nice to have, but I'm not sure if and how that can be done. >>> So, I came up with the following patch to add back the V4L2_BUF_CAP_SUPPORTS_DELETE_BUFS >>> capability. If the DELETE_BUFS ioctl is valid, then it sets this capability >>> before calling vidioc_reqbufs or vidioc_create_bufs. So right now it will set >>> this for any queue. If we ever want to disable this for a specific queue, then >>> either the driver has to override these two ops and clear the flag, or a new >>> vb2_queue flag (e.g. disable_delete_bufs) is added and vb2_set_flags_and_caps() >>> will clear that capability based on that flag. >>> >>> In any case, for now just set it for both queues by default. >>> >>> If you agree that this is a good way to proceed, then can you incorporate this >>> into a v20? You can add the documentation for this cap from the v17 version. >> Do you want it to be a separate patch or included in the patch introducing DELETE_BUFS ioctl ? > Up to you, whatever makes the most sense.
I will include it in DELETE_BUFS patch because it is strongly related to it.
Regards, Benjamin
> > Regards, > > Hans > >>> Regards, >>> >>> Hans >>> >>> Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl> >>> --- >>> diff --git a/drivers/media/common/videobuf2/videobuf2-v4l2.c b/drivers/media/common/videobuf2/videobuf2-v4l2.c >>> index 8e437104f9c1..64f2d662d068 100644 >>> --- a/drivers/media/common/videobuf2/videobuf2-v4l2.c >>> +++ b/drivers/media/common/videobuf2/videobuf2-v4l2.c >>> @@ -685,7 +685,7 @@ static void vb2_set_flags_and_caps(struct vb2_queue *q, u32 memory, >>> *flags &= V4L2_MEMORY_FLAG_NON_COHERENT; >>> } >>> >>> - *caps = V4L2_BUF_CAP_SUPPORTS_ORPHANED_BUFS; >>> + *caps |= V4L2_BUF_CAP_SUPPORTS_ORPHANED_BUFS; >>> if (q->io_modes & VB2_MMAP) >>> *caps |= V4L2_BUF_CAP_SUPPORTS_MMAP; >>> if (q->io_modes & VB2_USERPTR) >>> diff --git a/drivers/media/v4l2-core/v4l2-ioctl.c b/drivers/media/v4l2-core/v4l2-ioctl.c >>> index a172d33edd19..45bc705e171e 100644 >>> --- a/drivers/media/v4l2-core/v4l2-ioctl.c >>> +++ b/drivers/media/v4l2-core/v4l2-ioctl.c >>> @@ -2100,6 +2100,7 @@ static int v4l_overlay(const struct v4l2_ioctl_ops *ops, >>> static int v4l_reqbufs(const struct v4l2_ioctl_ops *ops, >>> struct file *file, void *fh, void *arg) >>> { >>> + struct video_device *vfd = video_devdata(file); >>> struct v4l2_requestbuffers *p = arg; >>> int ret = check_fmt(file, p->type); >>> >>> @@ -2108,6 +2109,9 @@ static int v4l_reqbufs(const struct v4l2_ioctl_ops *ops, >>> >>> memset_after(p, 0, flags); >>> >>> + if (is_valid_ioctl(vfd, VIDIOC_DELETE_BUFS)) >>> + p->capabilities = V4L2_BUF_CAP_SUPPORTS_DELETE_BUFS; >>> + >>> return ops->vidioc_reqbufs(file, fh, p); >>> } >>> >>> @@ -2141,6 +2145,7 @@ static int v4l_dqbuf(const struct v4l2_ioctl_ops *ops, >>> static int v4l_create_bufs(const struct v4l2_ioctl_ops *ops, >>> struct file *file, void *fh, void *arg) >>> { >>> + struct video_device *vfd = video_devdata(file); >>> struct v4l2_create_buffers *create = arg; >>> int ret = check_fmt(file, create->format.type); >>> >>> @@ -2151,6 +2156,9 @@ static int v4l_create_bufs(const struct v4l2_ioctl_ops *ops, >>> >>> v4l_sanitize_format(&create->format); >>> >>> + if (is_valid_ioctl(vfd, VIDIOC_DELETE_BUFS)) >>> + create->capabilities = V4L2_BUF_CAP_SUPPORTS_DELETE_BUFS; >>> + >>> ret = ops->vidioc_create_bufs(file, fh, create); >>> >>> if (create->format.type == V4L2_BUF_TYPE_VIDEO_CAPTURE || >>> diff --git a/include/uapi/linux/videodev2.h b/include/uapi/linux/videodev2.h >>> index 03443833aaaa..da307f46f903 100644 >>> --- a/include/uapi/linux/videodev2.h >>> +++ b/include/uapi/linux/videodev2.h >>> @@ -1036,6 +1036,7 @@ struct v4l2_requestbuffers { >>> #define V4L2_BUF_CAP_SUPPORTS_M2M_HOLD_CAPTURE_BUF (1 << 5) >>> #define V4L2_BUF_CAP_SUPPORTS_MMAP_CACHE_HINTS (1 << 6) >>> #define V4L2_BUF_CAP_SUPPORTS_MAX_NUM_BUFFERS (1 << 7) >>> +#define V4L2_BUF_CAP_SUPPORTS_DELETE_BUFS (1 << 8) >>> >>> /** >>> * struct v4l2_plane - plane info for multi-planar buffers >>> >>> >>>
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