[linux-dvb] [PATCH] mxl500x: Add module parameter to enable/disable debug messages

Gurumurti Laxman Maharana gurumurti at nkindia.com
Sat Apr 26 13:52:52 CEST 2008


Hi all
I would like to implemet CI in dvbstream program. How should i go about.
Can any body in this regard.
Thanks withs regards


> On Fri, 2008-04-25 at 14:55 +1000, Nick Andrew wrote:
>> On Thu, Apr 24, 2008 at 11:16:18PM -0400, Andy Walls wrote:
>> > +#define dprintk(level, fmt, arg...)
>>     \
>> > +	do {                                                              \
>> > +		if (debug >= level)                                       \
>> > +			printk(KERN_DEBUG "%s: " fmt, "mxl500x", ## arg); \
>> > +	} while (0)
>>
>> I think this code will be far more useful in kernel/printk.c rather
>> than every device driver and subsystem rolling their own (as seems to
>> happen at this time).
>
> Probably.  But I certainly don't have the credentials to move that idea
> very far forward. :)
>
>> Also see dev_dbg() and dev_printk() in include/linux/device.h.
>
> I looked at those, since Documentation/Codingstyle mentioned them.  They
> reduce right back down to almost the same "printk()" statement used in
> the macro above.
>
> If it's any real heartburn for anyone, the printk() in the macro quoted
> above could be changed to dev_dbg() with a change of arguments.  I'd
> need to scrounge up a "struct dev *" every time the module needs to
> print out a debug message though.  It's not very pretty (without another
> macro!) to dig that out of state->fe->dvb->device all the time, and it
> would be more perturbation than necessary just to squelch the spew into
> the kernel ring buffer and logs.
>
>
>> What those macros are missing is what you have here
>
> To give credit where credit is due, that macro is a work derived from
> the macro in linux/drivers/media/dvb/frontends/xc5000.c, (C) Xceive and
> Steven Toth.
>
>> - messages
>> printed or ignored depending on the value of a module variable
>> and/or parameter.
>
> Yes, dev_dbg() and friends are missing that.  My imagination fails me at
> the moment, as how to write a generically useful set of functions, with
> that characteristic, that a large subset of the drivers could use.
>
>
>> Nick.
>
> Thanks for the comments.
>
> Regards,
> Andy
>
>
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-- 
gurumurti at nkindia.com (m) 09324221887




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