The UVC driver has two video streams, one for the frames and another one
for the metadata. Both streams share most of the codebase, but only the
data stream declares support for DMABUF transfer mode.

I have tried the DMABUF transfer mode with CONFIG_DMABUF_HEAPS_SYSTEM
and the frames looked correct.

This patch announces the support for DMABUF for the metadata stream.
This is useful for apps/HALs that only want to support DMABUF.

Cc: stable@vger.kernel.org
Fixes: 088ead2552458 ("media: uvcvideo: Add a metadata device node")
Signed-off-by: Ricardo Ribalda <ribalda@chromium.org>
---
 drivers/media/usb/uvc/uvc_queue.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/drivers/media/usb/uvc/uvc_queue.c b/drivers/media/usb/uvc/uvc_queue.c
index 8b8f44b4a045..0eddd4f872ca 100644
--- a/drivers/media/usb/uvc/uvc_queue.c
+++ b/drivers/media/usb/uvc/uvc_queue.c
@@ -243,7 +243,7 @@ int uvc_queue_init(struct uvc_video_queue *queue, enum v4l2_buf_type type)
 	int ret;
 
 	queue->queue.type = type;
-	queue->queue.io_modes = VB2_MMAP | VB2_USERPTR;
+	queue->queue.io_modes = VB2_MMAP | VB2_USERPTR | VB2_DMABUF;
 	queue->queue.drv_priv = queue;
 	queue->queue.buf_struct_size = sizeof(struct uvc_buffer);
 	queue->queue.mem_ops = &vb2_vmalloc_memops;
@@ -256,7 +256,6 @@ int uvc_queue_init(struct uvc_video_queue *queue, enum v4l2_buf_type type)
 		queue->queue.ops = &uvc_meta_queue_qops;
 		break;
 	default:
-		queue->queue.io_modes |= VB2_DMABUF;
 		queue->queue.ops = &uvc_queue_qops;
 		break;
 	}

-- 
2.53.0.473.g4a7958ca14-goog

On Mon, Mar 09, 2026 at 03:01:54PM +0000, Ricardo Ribalda wrote:
> The UVC driver has two video streams, one for the frames and another one
> for the metadata. Both streams share most of the codebase, but only the
> data stream declares support for DMABUF transfer mode.
> 
> I have tried the DMABUF transfer mode with CONFIG_DMABUF_HEAPS_SYSTEM
> and the frames looked correct.
> 
> This patch announces the support for DMABUF for the metadata stream.
> This is useful for apps/HALs that only want to support DMABUF.

Is that something you plan to use in Android ?

> Cc: stable@vger.kernel.org
> Fixes: 088ead2552458 ("media: uvcvideo: Add a metadata device node")
> Signed-off-by: Ricardo Ribalda <ribalda@chromium.org>
> ---
>  drivers/media/usb/uvc/uvc_queue.c | 3 +--
>  1 file changed, 1 insertion(+), 2 deletions(-)
> 
> diff --git a/drivers/media/usb/uvc/uvc_queue.c b/drivers/media/usb/uvc/uvc_queue.c
> index 8b8f44b4a045..0eddd4f872ca 100644
> --- a/drivers/media/usb/uvc/uvc_queue.c
> +++ b/drivers/media/usb/uvc/uvc_queue.c
> @@ -243,7 +243,7 @@ int uvc_queue_init(struct uvc_video_queue *queue, enum v4l2_buf_type type)
>  	int ret;
>  
>  	queue->queue.type = type;
> -	queue->queue.io_modes = VB2_MMAP | VB2_USERPTR;
> +	queue->queue.io_modes = VB2_MMAP | VB2_USERPTR | VB2_DMABUF;

One day we should start warning about USERPTR being deprecated.

Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

>  	queue->queue.drv_priv = queue;
>  	queue->queue.buf_struct_size = sizeof(struct uvc_buffer);
>  	queue->queue.mem_ops = &vb2_vmalloc_memops;
> @@ -256,7 +256,6 @@ int uvc_queue_init(struct uvc_video_queue *queue, enum v4l2_buf_type type)
>  		queue->queue.ops = &uvc_meta_queue_qops;
>  		break;
>  	default:
> -		queue->queue.io_modes |= VB2_DMABUF;
>  		queue->queue.ops = &uvc_queue_qops;
>  		break;
>  	}
> 

-- 
Regards,

Laurent Pinchart

Hi,

On 9-Mar-26 4:01 PM, Ricardo Ribalda wrote:
> The UVC driver has two video streams, one for the frames and another one
> for the metadata. Both streams share most of the codebase, but only the
> data stream declares support for DMABUF transfer mode.
> 
> I have tried the DMABUF transfer mode with CONFIG_DMABUF_HEAPS_SYSTEM
> and the frames looked correct.
> 
> This patch announces the support for DMABUF for the metadata stream.
> This is useful for apps/HALs that only want to support DMABUF.
> 
> Cc: stable@vger.kernel.org
> Fixes: 088ead2552458 ("media: uvcvideo: Add a metadata device node")
> Signed-off-by: Ricardo Ribalda <ribalda@chromium.org>

Thanks, patch looks good to me:

Reviewed-by: Hans de Goede <johannes.goede@oss.qualcomm.com>

Regards,

Hans



> ---
>  drivers/media/usb/uvc/uvc_queue.c | 3 +--
>  1 file changed, 1 insertion(+), 2 deletions(-)
> 
> diff --git a/drivers/media/usb/uvc/uvc_queue.c b/drivers/media/usb/uvc/uvc_queue.c
> index 8b8f44b4a045..0eddd4f872ca 100644
> --- a/drivers/media/usb/uvc/uvc_queue.c
> +++ b/drivers/media/usb/uvc/uvc_queue.c
> @@ -243,7 +243,7 @@ int uvc_queue_init(struct uvc_video_queue *queue, enum v4l2_buf_type type)
>  	int ret;
>  
>  	queue->queue.type = type;
> -	queue->queue.io_modes = VB2_MMAP | VB2_USERPTR;
> +	queue->queue.io_modes = VB2_MMAP | VB2_USERPTR | VB2_DMABUF;
>  	queue->queue.drv_priv = queue;
>  	queue->queue.buf_struct_size = sizeof(struct uvc_buffer);
>  	queue->queue.mem_ops = &vb2_vmalloc_memops;
> @@ -256,7 +256,6 @@ int uvc_queue_init(struct uvc_video_queue *queue, enum v4l2_buf_type type)
>  		queue->queue.ops = &uvc_meta_queue_qops;
>  		break;
>  	default:
> -		queue->queue.io_modes |= VB2_DMABUF;
>  		queue->queue.ops = &uvc_queue_qops;
>  		break;
>  	}
>