* enable dynamic debug - doubt
@ 2015-11-17 12:40 Muni Sekhar
2015-11-18 19:12 ` Andy Shevchenko
2015-11-18 21:08 ` Peter Hurley
0 siblings, 2 replies; 4+ messages in thread
From: Muni Sekhar @ 2015-11-17 12:40 UTC (permalink / raw)
To: linux-kernel
[ 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?
--
Thanks,
Sekhar
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: enable dynamic debug - doubt
2015-11-17 12:40 enable dynamic debug - doubt Muni Sekhar
@ 2015-11-18 19:12 ` Andy Shevchenko
2015-11-18 21:08 ` Peter Hurley
1 sibling, 0 replies; 4+ messages in thread
From: Andy Shevchenko @ 2015-11-18 19:12 UTC (permalink / raw)
To: Muni Sekhar; +Cc: linux-kernel
On Tue, Nov 17, 2015 at 2:40 PM, Muni Sekhar <munisekharrms@gmail.com> 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
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: enable dynamic debug - doubt
2015-11-17 12:40 enable dynamic debug - doubt Muni Sekhar
2015-11-18 19:12 ` Andy Shevchenko
@ 2015-11-18 21:08 ` Peter Hurley
2015-11-19 8:47 ` Muni Sekhar
1 sibling, 1 reply; 4+ messages in thread
From: Peter Hurley @ 2015-11-18 21:08 UTC (permalink / raw)
To: Muni Sekhar, linux-kernel
On 11/17/2015 07:40 AM, Muni Sekhar 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).
That's not the only method. You'll want to read
Documentation/dynamic-debug-howto.txt; specifically, "Debug Messages at
Module Initialization Time" for ways to enable dynamic debug messages at
module load time.
Regards,
Peter Hurley
> 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?
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: enable dynamic debug - doubt
2015-11-18 21:08 ` Peter Hurley
@ 2015-11-19 8:47 ` Muni Sekhar
0 siblings, 0 replies; 4+ messages in thread
From: Muni Sekhar @ 2015-11-19 8:47 UTC (permalink / raw)
To: Peter Hurley; +Cc: linux-kernel
On Thu, Nov 19, 2015 at 2:38 AM, Peter Hurley <peter@hurleysoftware.com> wrote:
>
> On 11/17/2015 07:40 AM, Muni Sekhar 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).
>
> That's not the only method. You'll want to read
> Documentation/dynamic-debug-howto.txt; specifically, "Debug Messages at
> Module Initialization Time" for ways to enable dynamic debug messages at
> module load time.
>
> Regards,
> Peter Hurley
>
> > 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?
>
>
I just glanced through the Documentation/dynamic-debug-howto.txt and
now I am able to enable "Debug Messages at Module Initialization
Time".
Thanks Peter & Andy for the clarification.
--
Thanks,
Sekhar
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2015-11-19 8:47 UTC | newest]
Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
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2015-11-17 12:40 enable dynamic debug - doubt Muni Sekhar
2015-11-18 19:12 ` Andy Shevchenko
2015-11-18 21:08 ` Peter Hurley
2015-11-19 8:47 ` Muni Sekhar
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