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[35.199.49.112]) by smtp.gmail.com with ESMTPSA id g3-20020ac842c3000000b0041977932fc6sm385334qtm.18.2023.10.19.23.41.47 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 19 Oct 2023 23:41:48 -0700 (PDT) From: Ricardo Ribalda Date: Fri, 20 Oct 2023 06:41:45 +0000 Subject: [PATCH] media: uvcvideo: Implement V4L2_EVENT_FRAME_SYNC MIME-Version: 1.0 Message-Id: <20231020-uvc-event-v1-1-3baa0e9f6952@chromium.org> X-B4-Tracking: v=1; b=H4sIACghMmUC/x2NQQrDMAwEvxJ0rsB2bvlKyMGy5UZglGI3phDy9 4geZ5llLujchDss0wWNh3Q51MC/Jkh71DejZGMILszeBYfnSMiD9Yt5zp6IcqJQwHyKnZFa1LT bQ89abfw0LvL7B9btvh+GRYyrcAAAAA== To: Laurent Pinchart , Mauro Carvalho Chehab , Ricardo Ribalda Cc: linux-media@vger.kernel.org, linux-kernel@vger.kernel.org, Esker Wong X-Mailer: b4 0.12.2 Precedence: bulk List-ID: X-Mailing-List: linux-media@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. --- drivers/media/usb/uvc/uvc_v4l2.c | 2 ++ drivers/media/usb/uvc/uvc_video.c | 8 +++++++- 2 files changed, 9 insertions(+), 1 deletion(-) --- base-commit: ce55c22ec8b223a90ff3e084d842f73cfba35588 change-id: 20231020-uvc-event-d3d1bbbdcb2f Best regards, diff --git a/drivers/media/usb/uvc/uvc_v4l2.c b/drivers/media/usb/uvc/uvc_v4l2.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..1d4b4807b005 100644 --- a/drivers/media/usb/uvc/uvc_video.c +++ b/drivers/media/usb/uvc/uvc_video.c @@ -1073,9 +1073,15 @@ static int uvc_video_decode_start(struct uvc_streaming *stream, * that discontinuous sequence numbers always indicate lost frames. */ if (stream->last_fid != fid) { - stream->sequence++; + struct v4l2_event event = { + .type = V4L2_EVENT_FRAME_SYNC, + .u.frame_sync.frame_sequence = ++stream->sequence, + }; + if (stream->sequence) uvc_video_stats_update(stream); + + v4l2_event_queue(&stream->vdev, &event); } uvc_video_clock_decode(stream, buf, data, len);