2024-01-26 00:53:50

by Abhishek Pandit-Subedi

[permalink] [raw]
Subject: [PATCH] coding-style: Add guidance to prefer dev_dbg

During review, it was suggested that drivers only emit messages when
something is wrong or it is a debug message. Document this as a formal
recommendation.

https://lore.kernel.org/linux-usb/2024012525-alienate-frown-916b@gregkh/

Signed-off-by: Abhishek Pandit-Subedi <[email protected]>
---
I'm sending up the change to documentation while this is still fresh.
Will send an update to checkpatch.pl afterwards.

Documentation/process/coding-style.rst | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/Documentation/process/coding-style.rst b/Documentation/process/coding-style.rst
index c48382c6b477..f8ec23fa89bc 100644
--- a/Documentation/process/coding-style.rst
+++ b/Documentation/process/coding-style.rst
@@ -899,7 +899,8 @@ which you should use to make sure messages are matched to the right device
and driver, and are tagged with the right level: dev_err(), dev_warn(),
dev_info(), and so forth. For messages that aren't associated with a
particular device, <linux/printk.h> defines pr_notice(), pr_info(),
-pr_warn(), pr_err(), etc.
+pr_warn(), pr_err(), etc. When drivers are working properly they are quiet,
+so prefer to use dev_dbg/pr_debug unless something is wrong.

Coming up with good debugging messages can be quite a challenge; and once
you have them, they can be a huge help for remote troubleshooting. However
--
2.43.0.429.g432eaa2c6b-goog



2024-01-26 01:28:50

by Greg KH

[permalink] [raw]
Subject: Re: [PATCH] coding-style: Add guidance to prefer dev_dbg

On Thu, Jan 25, 2024 at 04:53:11PM -0800, Abhishek Pandit-Subedi wrote:
> During review, it was suggested that drivers only emit messages when
> something is wrong or it is a debug message. Document this as a formal
> recommendation.
>
> https://lore.kernel.org/linux-usb/2024012525-alienate-frown-916b@gregkh/
>
> Signed-off-by: Abhishek Pandit-Subedi <[email protected]>

Acked-by: Greg Kroah-Hartman <[email protected]>

2024-01-30 21:03:52

by Jonathan Corbet

[permalink] [raw]
Subject: Re: [PATCH] coding-style: Add guidance to prefer dev_dbg

Abhishek Pandit-Subedi <[email protected]> writes:

> During review, it was suggested that drivers only emit messages when
> something is wrong or it is a debug message. Document this as a formal
> recommendation.
>
> https://lore.kernel.org/linux-usb/2024012525-alienate-frown-916b@gregkh/
>
> Signed-off-by: Abhishek Pandit-Subedi <[email protected]>
> ---
> I'm sending up the change to documentation while this is still fresh.
> Will send an update to checkpatch.pl afterwards.
>
> Documentation/process/coding-style.rst | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/Documentation/process/coding-style.rst b/Documentation/process/coding-style.rst
> index c48382c6b477..f8ec23fa89bc 100644
> --- a/Documentation/process/coding-style.rst
> +++ b/Documentation/process/coding-style.rst
> @@ -899,7 +899,8 @@ which you should use to make sure messages are matched to the right device
> and driver, and are tagged with the right level: dev_err(), dev_warn(),
> dev_info(), and so forth. For messages that aren't associated with a
> particular device, <linux/printk.h> defines pr_notice(), pr_info(),
> -pr_warn(), pr_err(), etc.
> +pr_warn(), pr_err(), etc. When drivers are working properly they are quiet,
> +so prefer to use dev_dbg/pr_debug unless something is wrong.
>

Applied, thanks.

jon