Re: [Qemu-devel] [PATCH V3 2/2] sdhci: Change debug prints to compile unconditionally

[Markus Armbruster]

Sai Pavan Boddu <address@hidden> writes:

>> -----Original Message-----
>> From: Markus Armbruster [mailto:address@hidden
>> Sent: Monday, September 07, 2015 1:05 PM
>> To: Sai Pavan Boddu
>> Cc: address@hidden; address@hidden;
>> address@hidden; address@hidden; Sai Pavan Boddu; Edgar
>> Iglesias; Alistair Francis
>> Subject: Re: [Qemu-devel] [PATCH V3 2/2] sdhci: Change debug prints to
>> compile unconditionally
>> 
>> Sai Pavan Boddu <address@hidden> writes:
>> 
>> > Conditionaly compilation hides few type mismatch warnings, fix it to
>> > compile unconditioinal.
>> >
>> > Signed-off-by: Sai Pavan Boddu <address@hidden>
>> > Suggested-by: Eric Blake <address@hidden>
>> 
>> No objection to this patch, but have you considered tracepoints?
>> See docs/tracing.txt.
>
> [Sai Pavan ] No, I didn’t do that. Actually no knowledge on that. Let
> me figure it out what it does. Even better if you can just explain in
> few lines, for what trace tool is used?

For a simple example of how to convert from debug prints to tracepoints,
check out commit f6e3534.

Perhaps the simplest way to get the debugging output then is the
"stderr" backend you get with "configure --enable-trace-backend=stderr".
Run QEMU with "-trace events=foo", where file foo contains a list of
events to enable.  To get all the tracepoints added by the commit above,
try this one-element list:

    fw_cfg_*

Hope this suffices to get you started.