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[35.199.49.112]) by smtp.gmail.com with ESMTPSA id z10-20020a0cfc0a000000b0066d0f35554asm3314339qvo.79.2023.11.06.02.52.33 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 06 Nov 2023 02:52:34 -0800 (PST) From: Ricardo Ribalda Date: Mon, 06 Nov 2023 10:52:27 +0000 Subject: [PATCH v2] media: uvcvideo: Implement V4L2_EVENT_FRAME_SYNC MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Message-Id: <20231106-uvc-event-v2-1-7d8e36f0df16@chromium.org> X-B4-Tracking: v=1; b=H4sIAGvFSGUC/22NTQ6DIBBGr2JYdxrAtIld9R6NCwZGmUShASU2x ruXuu7yvXw/u8iUmLJ4NLtIVDhzDBX0pRHWmzASsKsstNStklrCWixQobCAa51CRGdRD6Lm0WQ CTCZYXxthnaYq34kG3s6DV1/Zc15i+px/Rf3sv+miQEGLxkjqhnt300/rU5x5na8xjaI/juMLp IC7lroAAAA= To: Laurent Pinchart , Mauro Carvalho Chehab , Ricardo Ribalda Cc: linux-media@vger.kernel.org, linux-kernel@vger.kernel.org, Esker Wong X-Mailer: b4 0.12.3 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Add support for the frame_sync event, so user-space can become aware earlier of new frames. Suggested-by: Esker Wong Tested-by: Esker Wong Signed-off-by: Ricardo Ribalda --- We have measured a latency of around 30msecs between frame sync and dqbuf. --- Changes in v2: - Suggested by Laurent. Split sequence++ and event init. - Link to v1: https://lore.kernel.org/r/20231020-uvc-event-v1-1-3baa0e9f695= 2@chromium.org --- drivers/media/usb/uvc/uvc_v4l2.c | 2 ++ drivers/media/usb/uvc/uvc_video.c | 7 +++++++ 2 files changed, 9 insertions(+) diff --git a/drivers/media/usb/uvc/uvc_v4l2.c b/drivers/media/usb/uvc/uvc_v= 4l2.c index f4988f03640a..9f3fb5fd2375 100644 --- a/drivers/media/usb/uvc/uvc_v4l2.c +++ b/drivers/media/usb/uvc/uvc_v4l2.c @@ -1352,6 +1352,8 @@ static int uvc_ioctl_subscribe_event(struct v4l2_fh *= fh, switch (sub->type) { case V4L2_EVENT_CTRL: return v4l2_event_subscribe(fh, sub, 0, &uvc_ctrl_sub_ev_ops); + case V4L2_EVENT_FRAME_SYNC: + return v4l2_event_subscribe(fh, sub, 0, NULL); default: return -EINVAL; } diff --git a/drivers/media/usb/uvc/uvc_video.c b/drivers/media/usb/uvc/uvc_= video.c index 28dde08ec6c5..4f3a510ca4fe 100644 --- a/drivers/media/usb/uvc/uvc_video.c +++ b/drivers/media/usb/uvc/uvc_video.c @@ -1073,9 +1073,16 @@ static int uvc_video_decode_start(struct uvc_streami= ng *stream, * that discontinuous sequence numbers always indicate lost frames. */ if (stream->last_fid !=3D fid) { + struct v4l2_event event =3D { + .type =3D V4L2_EVENT_FRAME_SYNC, + }; + stream->sequence++; if (stream->sequence) uvc_video_stats_update(stream); + + event.u.frame_sync.frame_sequence =3D stream->sequence, + v4l2_event_queue(&stream->vdev, &event); } =20 uvc_video_clock_decode(stream, buf, data, len); --- base-commit: ce55c22ec8b223a90ff3e084d842f73cfba35588 change-id: 20231020-uvc-event-d3d1bbbdcb2f Best regards, --=20 Ricardo Ribalda