Re: [PATCH 2/2] i2c-hid: remove mostly useless parameter 'debug'

[Andy Shevchenko <andriy.shevchenko@linux.intel.com>]

On Mon, 2013-08-05 at 11:26 +0200, Jiri Kosina wrote: 
> On Fri, 2 Aug 2013, Benjamin Tissoires wrote:
> 
> > > With only one condition if dynamic debug is enabled in kernel.
> > > So, it would be nice to gather opinions, however, the decision is
> > > totally depends on type of user who wants to debug the module.
> > > 
> > Yep, I agree that Jiri's opinion would be helpful.
> > 
> > Meanwhile, we could also wait a little for more i2c-hid to hit the
> > market and to be widely tested, and then remove the debug flag. We
> > should also remove the debug events in get_i2c_hid_get_input() which
> > would pollute systems without dynamic debugging but with the DEBUG
> > config still enabled.
> 
> Well, it doesn't seem to make too much sense to me to have generic/bus use 
> hid_dbg() (although it's used very rarely) and a "sub-driver" use 
> something else.
> 
> Basically the options I see:
> 
> - keep i2c-hid as is
> - convert the whole drivers/hid to dev_dbg()
> - introduce another hid debugfs file in parallel to rdesc and events for 
>   these types of messages

Debugfs could be off in the kernel configuration. Whatever we choose
there will be a kernel that has a disabled option which prevents to
debug: either debugging is turned off, or driver itself.


There is another possibility as well:
instead of dev_dbg() we may add trace points and subscribe to them from
userspace via perf, for example.

-- 
Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Intel Finland Oy