grey- and blacklisting drivers [Was: Re: Using the "best available" driver]

[Kay Sievers]

On Tue, Dec 13, 2005 at 08:39:57PM +0100, Dominik Brodowski wrote:
> Hi,
> 
> On Tue, Dec 13, 2005 at 05:55:04AM +0100, Kay Sievers wrote:
> > New version, which does not do the dirty "default parameters" trick. It
> > depends on a regular module parameter, if "bind_mode" control at module
> > load or boot prompt is needed. It uses "auto" and "manual" as the values
> > and the sysfs file in the driver directory is called "bind_mode".
> 
> 
> The only thing which worries me is that we add quite some bytes to the
> kernel here... What do you think about this?
> 
> #define module_param_bind_mode(driver)					\
> 	module_param_named(dont_bind, &driver->bind_mode, uint, 0);	\
> 	MODULE_PARM_DESC(bind_mode, "Do not bind this driver to "	\
> 				"devices automatically.");
> 
> Then we'd need to add
> 
> module_param_named(&ov511_driver.driver);
> 
> to ov511.c and get the same functionality.

Yes, that we need to decide. I just wanted to see the alternative approach
and posted it. We need to find out if we want:
  "default module parameters"
    - which would work for all modules, without changes
    - like the first patch, but in a more generic way that
      also implements built-in early parameter parsing
or:
    "only modular drivers init support by default"
    - will work fine with the current infrastructure, but modules
      need to have the parameter added if they want boot parameter
      support

If "default module parameters" are something that is considered useful
for other possible use cases too, we may just go for it.

And another thing is the prameters textual value like "auto" and
"manual". If we never add a third option to it, we may stick with the sysfs
boolean, which is smaller and simpler to implement. Not sure what's the
best here.

Thanks,
Kay