[Linux-fbdev-devel] Re: Aty128fb as a module with options support

[Petr V. <VAN...@vc...>]

On  8 Jun 01 at 21:34, Otto Wyss wrote:
> 
> Since the driver compiled into the kernel (2.4.3, i386) only supports
> options "noaccel" and "nomtrr" I tried to test these options first. But
> it seems I'm not successful. While I'm not sure of the "noaccel" option
> (no visible effect), even when specifying "nomtrr" the syslog showed
> "aty128fb: Rage128 MTRR set to on".

You can decide for two ways:
(1) use different options name and leave parsing on insmod/modprobe
    (this is what matroxfb does) or
(2) use one string option and leave fbdev driver to parse it yourself

> After MODULE_DESCRIPTION I added the following line:
>  static const char *option __initdata = NULL;
>  MODULE_PARM(noaccel, "i");
>  MODULE_PARM_DESC(noaccel, "Disables hardware acceleration (0 or
> 1=disabled)  (default=0)");

So 'insmod aty128fb noaccel=1' should work.

>  #ifdef CONFIG_MTRR
>  MODULE_PARM(mtrr, "i");
>  MODULE_PARM_DESC(mtrr, "Disables MTRR support (0 or 1=disabled) (default=0)");
>  #endif

And 'insmod aty128fb mtrr=0' ... How you tried to pass options to aty128fb?
If you type 'insmod aty128fb nomtrr', insmod should loudly complain
that it does not know what to do with 'nomtrr'.
These both options are attempt to use way (1) as described above.

> After init_module(void) { I added the following line:
>     aty128fb_setup(option);

And here you are trying to use method (2). But to get this to work
you must do:

(a) add 

char* option = NULL;
MODULE_PARM(option, "s");
MODULE_PARM_DESC(option, "Use option=nomtrr to disable mtrr...");

(b) make sure that you are passing this global variable as argument
to aty128fb_setup. As there is no 'option' variable, you should receive
an error from compiler...

(c) then use 'insmod aty128fb option="nomtrr,noaccel"' - make sure
that you are using quotes around option=... (maybe you have to type
\" in shell), otherwise insmod will treat it as two values assigned
to option variable - which is not possible.

But in any of these cases kernel boot command line (video=aty128fb:...)
cannot have any effect on modularized aty128fb behavior!
                                                Petr Vandrovec
                                                van...@vc...