From: Ricardo Ribalda Date: Mon, 9 Mar 2026 15:01:56 +0000 (+0000) Subject: media: uvcvideo: Allow userspace to increase the meta buffersize X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=2ac27db04608a7ce4d46a3bf23d2262c7b20db38;p=thirdparty%2Fkernel%2Fstable.git media: uvcvideo: Allow userspace to increase the meta buffersize Now we have the metadata size hardcoded to 10 KiB, this is a value that works fine for bulk cameras or frames with no extra metadata. But not for all usecases. We have seen some cameras that produce more metadata per frame. Eg: Frame 1 captured (Bytes: 11154) Frame 2 captured (Bytes: 11616) Frame 3 captured (Bytes: 11374) Frame 4 captured (Bytes: 11132) Frame 5 captured (Bytes: 11594) Frame 6 captured (Bytes: 11352) Frame 7 captured (Bytes: 11110) Frame 8 captured (Bytes: 11572) Frame 9 captured (Bytes: 11308) When this happens, the driver (correctly) marks the metadata as ERROR. This patch let userspace set bigger buffersize via S_FMT. Signed-off-by: Ricardo Ribalda Reviewed-by: Hans de Goede Reviewed-by: Laurent Pinchart Link: https://patch.msgid.link/20260309-uvc-metadata-dmabuf-v1-3-fc8b87bd29c5@chromium.org Signed-off-by: Laurent Pinchart Signed-off-by: Hans Verkuil --- diff --git a/drivers/media/usb/uvc/uvc_metadata.c b/drivers/media/usb/uvc/uvc_metadata.c index 0a906ae3f971..9de8aba1229e 100644 --- a/drivers/media/usb/uvc/uvc_metadata.c +++ b/drivers/media/usb/uvc/uvc_metadata.c @@ -50,7 +50,7 @@ static int uvc_meta_v4l2_get_format(struct file *file, void *priv, return -EINVAL; fmt->dataformat = stream->meta.format; - fmt->buffersize = UVC_METADATA_BUF_SIZE; + fmt->buffersize = stream->meta.buffersize; return 0; } @@ -63,6 +63,7 @@ static int uvc_meta_v4l2_try_format(struct file *file, void *priv, struct uvc_device *dev = stream->dev; struct v4l2_meta_format *fmt = &format->fmt.meta; u32 fmeta = V4L2_META_FMT_UVC; + u32 buffersize; if (format->type != vfh->vdev->queue->type) return -EINVAL; @@ -74,10 +75,12 @@ static int uvc_meta_v4l2_try_format(struct file *file, void *priv, } } + buffersize = max(UVC_METADATA_BUF_MIN_SIZE, fmt->buffersize); + memset(fmt, 0, sizeof(*fmt)); fmt->dataformat = fmeta; - fmt->buffersize = UVC_METADATA_BUF_SIZE; + fmt->buffersize = buffersize; return 0; } @@ -103,6 +106,7 @@ static int uvc_meta_v4l2_set_format(struct file *file, void *priv, return -EBUSY; stream->meta.format = fmt->dataformat; + stream->meta.buffersize = fmt->buffersize; return 0; } @@ -229,6 +233,7 @@ int uvc_meta_register(struct uvc_streaming *stream) struct uvc_video_queue *queue = &stream->meta.queue; stream->meta.format = V4L2_META_FMT_UVC; + stream->meta.buffersize = UVC_METADATA_BUF_MIN_SIZE; return uvc_register_video_device(dev, stream, queue, V4L2_BUF_TYPE_META_CAPTURE, diff --git a/drivers/media/usb/uvc/uvc_queue.c b/drivers/media/usb/uvc/uvc_queue.c index 68ed2883edb2..89206f761006 100644 --- a/drivers/media/usb/uvc/uvc_queue.c +++ b/drivers/media/usb/uvc/uvc_queue.c @@ -83,7 +83,7 @@ static int uvc_queue_setup(struct vb2_queue *vq, switch (vq->type) { case V4L2_BUF_TYPE_META_CAPTURE: - size = UVC_METADATA_BUF_SIZE; + size = stream->meta.buffersize; break; default: diff --git a/drivers/media/usb/uvc/uvcvideo.h b/drivers/media/usb/uvc/uvcvideo.h index 9b4849fda12f..5ba698d2a23d 100644 --- a/drivers/media/usb/uvc/uvcvideo.h +++ b/drivers/media/usb/uvc/uvcvideo.h @@ -409,7 +409,7 @@ struct uvc_stats_stream { unsigned int max_sof; /* Maximum STC.SOF value */ }; -#define UVC_METADATA_BUF_SIZE 10240 +#define UVC_METADATA_BUF_MIN_SIZE 10240 /** * struct uvc_copy_op: Context structure to schedule asynchronous memcpy @@ -482,6 +482,7 @@ struct uvc_streaming { struct { struct uvc_video_queue queue; u32 format; + u32 buffersize; } meta; /* Context data used by the bulk completion handler. */