The Hantro driver uses a hardcoded value for the bus_info field in the
media device and |struct v4l2_capability|. This worked well when there
was just one device. However with the iMX.8 series we are now seeing
two Hantro blocks on the same chip. The static bus_info is no longer
sufficient for differentiating devices.

Since commit f2d8b6917f3b ("media: v4l: ioctl: Set bus_info in
v4l_querycap()"), the V4L2 core provides a default value for the
bus_info field for platform and PCI devices. This value will match
the default value for media devices added by commit cef699749f37
("media: mc: Set bus_info in media_device_init()"). These defaults
are stable and device-specific.

Drop the static bus_info values from the hantro driver and use the
defaults.

Signed-off-by: Chen-Yu Tsai <wenst@chromium.org>
---
Changes since v1:
- Dropped unrelated Makefile change

 drivers/media/platform/verisilicon/hantro_drv.c  | 2 --
 drivers/media/platform/verisilicon/hantro_v4l2.c | 2 --
 2 files changed, 4 deletions(-)

diff --git a/drivers/media/platform/verisilicon/hantro_drv.c b/drivers/media/platform/verisilicon/hantro_drv.c
index 8cb4a68c9119..b0aeedae7b65 100644
--- a/drivers/media/platform/verisilicon/hantro_drv.c
+++ b/drivers/media/platform/verisilicon/hantro_drv.c
@@ -1050,8 +1050,6 @@ static int hantro_probe(struct platform_device *pdev)
 
 	vpu->mdev.dev = vpu->dev;
 	strscpy(vpu->mdev.model, DRIVER_NAME, sizeof(vpu->mdev.model));
-	strscpy(vpu->mdev.bus_info, "platform: " DRIVER_NAME,
-		sizeof(vpu->mdev.bus_info));
 	media_device_init(&vpu->mdev);
 	vpu->mdev.ops = &hantro_m2m_media_ops;
 	vpu->v4l2_dev.mdev = &vpu->mdev;
diff --git a/drivers/media/platform/verisilicon/hantro_v4l2.c b/drivers/media/platform/verisilicon/hantro_v4l2.c
index 2c7a805289e7..c1a116031013 100644
--- a/drivers/media/platform/verisilicon/hantro_v4l2.c
+++ b/drivers/media/platform/verisilicon/hantro_v4l2.c
@@ -142,8 +142,6 @@ static int vidioc_querycap(struct file *file, void *priv,
 
 	strscpy(cap->driver, vpu->dev->driver->name, sizeof(cap->driver));
 	strscpy(cap->card, vdev->name, sizeof(cap->card));
-	snprintf(cap->bus_info, sizeof(cap->bus_info), "platform: %s",
-		 vpu->dev->driver->name);
 	return 0;
 }
 
-- 
2.39.0.314.g84b9a713c41-goog

On Mon, Dec 26, 2022 at 01:26:06PM +0800, Chen-Yu Tsai wrote:
> The Hantro driver uses a hardcoded value for the bus_info field in the
> media device and |struct v4l2_capability|. This worked well when there
> was just one device. However with the iMX.8 series we are now seeing
> two Hantro blocks on the same chip. The static bus_info is no longer
> sufficient for differentiating devices.
> 
> Since commit f2d8b6917f3b ("media: v4l: ioctl: Set bus_info in
> v4l_querycap()"), the V4L2 core provides a default value for the
> bus_info field for platform and PCI devices. This value will match
> the default value for media devices added by commit cef699749f37
> ("media: mc: Set bus_info in media_device_init()"). These defaults
> are stable and device-specific.
> 
> Drop the static bus_info values from the hantro driver and use the
> defaults.
> 
> Signed-off-by: Chen-Yu Tsai <wenst@chromium.org>

Makes sense.

Reviewed-by: Ezequiel Garcia <ezequiel@vanguardiasur.com.ar>

Thanks!


> ---
> Changes since v1:
> - Dropped unrelated Makefile change
> 
>  drivers/media/platform/verisilicon/hantro_drv.c  | 2 --
>  drivers/media/platform/verisilicon/hantro_v4l2.c | 2 --
>  2 files changed, 4 deletions(-)
> 
> diff --git a/drivers/media/platform/verisilicon/hantro_drv.c b/drivers/media/platform/verisilicon/hantro_drv.c
> index 8cb4a68c9119..b0aeedae7b65 100644
> --- a/drivers/media/platform/verisilicon/hantro_drv.c
> +++ b/drivers/media/platform/verisilicon/hantro_drv.c
> @@ -1050,8 +1050,6 @@ static int hantro_probe(struct platform_device *pdev)
>  
>  	vpu->mdev.dev = vpu->dev;
>  	strscpy(vpu->mdev.model, DRIVER_NAME, sizeof(vpu->mdev.model));
> -	strscpy(vpu->mdev.bus_info, "platform: " DRIVER_NAME,
> -		sizeof(vpu->mdev.bus_info));
>  	media_device_init(&vpu->mdev);
>  	vpu->mdev.ops = &hantro_m2m_media_ops;
>  	vpu->v4l2_dev.mdev = &vpu->mdev;
> diff --git a/drivers/media/platform/verisilicon/hantro_v4l2.c b/drivers/media/platform/verisilicon/hantro_v4l2.c
> index 2c7a805289e7..c1a116031013 100644
> --- a/drivers/media/platform/verisilicon/hantro_v4l2.c
> +++ b/drivers/media/platform/verisilicon/hantro_v4l2.c
> @@ -142,8 +142,6 @@ static int vidioc_querycap(struct file *file, void *priv,
>  
>  	strscpy(cap->driver, vpu->dev->driver->name, sizeof(cap->driver));
>  	strscpy(cap->card, vdev->name, sizeof(cap->card));
> -	snprintf(cap->bus_info, sizeof(cap->bus_info), "platform: %s",
> -		 vpu->dev->driver->name);
>  	return 0;
>  }
>  
> -- 
> 2.39.0.314.g84b9a713c41-goog
>