# Re: \[PATCH\] visl: use canonical ftrace path

- From: Masami Hiramatsu (Google) \<mhiramat@kernel.org\>
- Date: 2023-08-31 00:12:38 
- List: linux-trace-kernel
- Page: https://ratatoskr.run/linux-trace-kernel/2023/08/2320262
- Thread: https://ratatoskr.run/linux-media/2023/08/2318924/t.md

```text
On Tue, 29 Aug 2023 14:46:01 -0600
Ross Zwisler [ref] wrote:

> From: Ross Zwisler <redacted>
> 
> The canonical location for the tracefs filesystem is at /sys/kernel/tracing.
> 
> But, from Documentation/trace/ftrace.rst:
> 
>   Before 4.1, all ftrace tracing control files were within the debugfs
>   file system, which is typically located at /sys/kernel/debug/tracing.
>   For backward compatibility, when mounting the debugfs file system,
>   the tracefs file system will be automatically mounted at:
> 
>   /sys/kernel/debug/tracing
> 
> Update the visl decoder driver documentation to use this tracefs path.
> 
> Signed-off-by: Ross Zwisler <redacted>

Looks good to me.

Reviewed-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>

Thanks!

> ---
>  Documentation/admin-guide/media/visl.rst | 6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)
> 
> diff --git a/Documentation/admin-guide/media/visl.rst b/Documentation/admin-guide/media/visl.rst
> index 7d2dc78341c9..4328c6c72d30 100644
> --- a/Documentation/admin-guide/media/visl.rst
> +++ b/Documentation/admin-guide/media/visl.rst
> @@ -78,7 +78,7 @@ The trace events are defined on a per-codec basis, e.g.:
>  
>  .. code-block:: bash
>  
> -        $ ls /sys/kernel/debug/tracing/events/ | grep visl
> +        $ ls /sys/kernel/tracing/events/ | grep visl
>          visl_fwht_controls
>          visl_h264_controls
>          visl_hevc_controls
> @@ -90,13 +90,13 @@ For example, in order to dump HEVC SPS data:
>  
>  .. code-block:: bash
>  
> -        $ echo 1 >  /sys/kernel/debug/tracing/events/visl_hevc_controls/v4l2_ctrl_hevc_sps/enable
> +        $ echo 1 >  /sys/kernel/tracing/events/visl_hevc_controls/v4l2_ctrl_hevc_sps/enable
>  
>  The SPS data will be dumped to the trace buffer, i.e.:
>  
>  .. code-block:: bash
>  
> -        $ cat /sys/kernel/debug/tracing/trace
> +        $ cat /sys/kernel/tracing/trace
>          video_parameter_set_id 0
>          seq_parameter_set_id 0
>          pic_width_in_luma_samples 1920
> -- 
> 2.42.0.rc2.253.gd59a3bf2b4-goog
> 


-- 
Masami Hiramatsu (Google) [ref]
```