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[34.88.69.27]) by smtp.gmail.com with ESMTPSA id 2adb3069b0e04-5a13d08cc0dsm2138003e87.80.2026.03.09.08.02.00 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 09 Mar 2026 08:02:00 -0700 (PDT) From: Ricardo Ribalda Date: Mon, 09 Mar 2026 15:01:56 +0000 Subject: [PATCH 3/3] media: uvcvideo: Allow userspace to increase the meta buffersize Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Message-Id: <20260309-uvc-metadata-dmabuf-v1-3-fc8b87bd29c5@chromium.org> References: <20260309-uvc-metadata-dmabuf-v1-0-fc8b87bd29c5@chromium.org> In-Reply-To: <20260309-uvc-metadata-dmabuf-v1-0-fc8b87bd29c5@chromium.org> To: Laurent Pinchart , Hans de Goede , Mauro Carvalho Chehab , Guennadi Liakhovetski Cc: linux-media@vger.kernel.org, linux-kernel@vger.kernel.org, Yunke Cao , Ricardo Ribalda X-Mailer: b4 0.14.3 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 --- drivers/media/usb/uvc/uvc_metadata.c | 9 +++++++-- drivers/media/usb/uvc/uvc_queue.c | 2 +- drivers/media/usb/uvc/uvcvideo.h | 3 ++- 3 files changed, 10 insertions(+), 4 deletions(-) diff --git a/drivers/media/usb/uvc/uvc_metadata.c b/drivers/media/usb/uvc/u= vc_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, vo= id *priv, return -EINVAL; =20 fmt->dataformat =3D stream->meta.format; - fmt->buffersize =3D UVC_METADATA_BUF_SIZE; + fmt->buffersize =3D stream->meta.buffersize; =20 return 0; } @@ -63,6 +63,7 @@ static int uvc_meta_v4l2_try_format(struct file *file, vo= id *priv, struct uvc_device *dev =3D stream->dev; struct v4l2_meta_format *fmt =3D &format->fmt.meta; u32 fmeta =3D V4L2_META_FMT_UVC; + u32 buffersize; =20 if (format->type !=3D vfh->vdev->queue->type) return -EINVAL; @@ -74,10 +75,12 @@ static int uvc_meta_v4l2_try_format(struct file *file, = void *priv, } } =20 + buffersize =3D max(UVC_METADATA_BUF_MIN_SIZE, fmt->buffersize); + memset(fmt, 0, sizeof(*fmt)); =20 fmt->dataformat =3D fmeta; - fmt->buffersize =3D UVC_METADATA_BUF_SIZE; + fmt->buffersize =3D buffersize; =20 return 0; } @@ -103,6 +106,7 @@ static int uvc_meta_v4l2_set_format(struct file *file, = void *priv, return -EBUSY; =20 stream->meta.format =3D fmt->dataformat; + stream->meta.buffersize =3D fmt->buffersize; =20 return 0; } @@ -229,6 +233,7 @@ int uvc_meta_register(struct uvc_streaming *stream) struct uvc_video_queue *queue =3D &stream->meta.queue; =20 stream->meta.format =3D V4L2_META_FMT_UVC; + stream->meta.buffersize =3D UVC_METADATA_BUF_MIN_SIZE; =20 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, =20 switch (vq->type) { case V4L2_BUF_TYPE_META_CAPTURE: - size =3D UVC_METADATA_BUF_SIZE; + size =3D stream->meta.buffersize; break; =20 default: diff --git a/drivers/media/usb/uvc/uvcvideo.h b/drivers/media/usb/uvc/uvcvi= deo.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 */ }; =20 -#define UVC_METADATA_BUF_SIZE 10240 +#define UVC_METADATA_BUF_MIN_SIZE 10240 =20 /** * 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; =20 /* Context data used by the bulk completion handler. */ --=20 2.53.0.473.g4a7958ca14-goog