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Subject: Re: [Bluez PATCH] doc: Add definition for Set Kernel Debug Level
From:   Marcel Holtmann <marcel@holtmann.org>
In-Reply-To: <20200120202708.111383-1-alainm@chromium.org>
Date:   Tue, 21 Jan 2020 17:20:54 +0100
Cc:     linux-bluetooth@vger.kernel.org
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Message-Id: <6E55772A-01D5-4616-B3DB-CC22B935C855@holtmann.org>
References: <20200120202708.111383-1-alainm@chromium.org>
To:     Alain Michaud <alainm@chromium.org>
Sender: linux-bluetooth-owner@vger.kernel.org
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Hi Alain,

> This command is used to by higher level applications to dynamically
> control the debug logging level of the kernel module.  This is
> particularly useful to collect debug information from customers filing
> feedback reports for issues that are difficult to reproduce outside of a
> customer's particular environement.
> 
> ---
> 
> doc/mgmt-api.txt | 25 +++++++++++++++++++++++++
> 1 file changed, 25 insertions(+)
> 
> diff --git a/doc/mgmt-api.txt b/doc/mgmt-api.txt
> index 1e59acc54..f2dba64d1 100644
> --- a/doc/mgmt-api.txt
> +++ b/doc/mgmt-api.txt
> @@ -3047,6 +3047,31 @@ Load Blocked Keys Command
> 	Possible errors:	Invalid Parameters
> 				Invalid Index
> 
> +Set Kernel Debug Logging Level Command
> +=======================
> +
> +	Command Code:		0x0047
> +	Controller Index: <controller id>
> +	Command Parameters : Debug_Logging_Level (1 octet)
> +
> +	This command is used to set the kernel debug logging level. This
> +	can be by higher level applications to facilitate dynamically
> +	controlling	the logging level produced by the Bluez kernel module.
> +
> +	Supported Debug_Logging_Level values:
> +		0 : No Logging
> +		1 : All debug information.
> +		All other values are reserved for future use.
> +
> +	When the kernel receives a value higher than the maximum supported
> +	value, the kernel module shall set it's logging level to the highest
> +	value it supports.
> +
> +	This command generates a Command Complete event on success or
> +	a Command Status event on failure.
> +
> +	Possible errors:	Invalid Parameters
> +				Invalid Index

I need a bit more explanation on how this is suppose to work and why the current dynamic_debug feature is not enough.

Regards

Marcel