Re: enable dynamic debug - doubt

From: Andy Shevchenko
Date: Wed Nov 18 2015 - 14:12:26 EST

On Tue, Nov 17, 2015 at 2:40 PM, Muni Sekhar <munisekharrms@xxxxxxxxx> wrote:
> [ Please keep me in CC as I'm not subscribed to the list]
> Hello,
> The behaviour of dynamic debug prints are controlled via writing to a
> control file in the 'debugfs'
> filesystem(<debugfs>/dynamic_debug/control).
> Here I would like to know what order should the echo(for eg: echo -n
> 'module sdhci +p' > /sys/kernel/debug/dynamic_debug/control) be
> applied in relation to the module load - before or after?

Just imagine how debugfs works. It has probes over the code where
*_dbg/debug() prints are used. Those special data structures are kept
in the specific part of the file / kernel. If there is no module, how
will kernel know that there is a portion of such data there?

With Best Regards,
Andy Shevchenko
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