Re: [PATCH 2/2] i2c: Add message transfer tracepoints for SMBUS [ver #2]
From: Wolfram Sang
Date: Thu Mar 13 2014 - 17:15:58 EST
On Thu, Mar 06, 2014 at 01:36:06PM +0000, David Howells wrote:
> The SMBUS tracepoints can be enabled thusly:
>
> echo 1 >/sys/kernel/debug/tracing/events/i2c/enable
>
> and will dump messages that can be viewed in /sys/kernel/debug/tracing/trace
> that look like:
>
> ... smbus_read: i2c-0 a=051 f=0000 c=fa BYTE_DATA
> ... smbus_reply: i2c-0 a=051 f=0000 c=fa BYTE_DATA l=1 [39]
> ... smbus_result: i2c-0 a=051 f=0000 c=fa BYTE_DATA rd res=0
>
> formatted as:
>
> i2c-<adapter-nr>
> a=<addr>
> f=<flags>
> c=<command>
> <protocol-name>
> <rd|wr>
> res=<result>
> l=<data-len>
> [<data-block>]
>
>
> The adapters to be traced can be selected by something like:
>
> echo adapter_nr==1 >/sys/kernel/debug/tracing/events/i2c/filter
>
> Note that this shares the same filter and enablement as i2c.
>
> Signed-off-by: David Howells <dhowells@xxxxxxxxxx>
> Reviewed-by: Steven Rostedt <rostedt@xxxxxxxxxxx>
Applied to for-next, thanks!
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