Re: query video dev node name using the V4L2 device driver name

[Laurent Pinchart <laurent.pinchart@ideasonboard.com>]

Hi Mingcheng,

On Monday 19 December 2011 11:21:03 Zhu, Mingcheng wrote:
> Hi Laurent and Sakari,
> 
> Current media entity contains a few fields to identify a dev node (name,
> type, group_id). The entity name is the v4l2 dev node name such as
> "/dev/video0" "/dev/video1". There is no information who is "/dev/video0"
> and who is /dev/video1". This makes that, after query the media_entity the
> application still could not figure out who is /dev/video1".

The media controller framework sets the video devnode entities names to the 
video device name, as provided in the video_device name field. That's 
automatic, so you should just ensure that your video_device name is properly 
set.

> However in V4L2 devices, there is a driver name that the vendor can assign
> a specific name such "WIFI CAPTURE" or BACK_CAMERA" to the driver name. Is
> it possible to add the driver name into the media_entity? This makes that,
> if the userspace application knows the driver name it can use the driver
> name to find the dev node.

Using the driver name isn't optimal, as a driver could create several video 
device nodes for the same hardware device. Those nodes should have different 
names, so you should use the video_device name field as explained above.

-- 
Regards,

Laurent Pinchart