Re: [PATCH] tdfxfb: mtrr support (2nd revision)

[Geert Uytterhoeven <geert@linux-m68k.org>]

On Tue, 31 Jul 2007, Krzysztof Helt wrote:
> This patch adds mtrr support to the tdfxfb driver.
> It also kills one redundant include and initialization value.
> 
> Signed-off-by: Krzysztof Helt <krzysztof.h1@wp.pl>
> 
> ---
> 
> This patch requires all previous tdfxfb patches sent to this list.
> It reduces ifdefs to only removing unused "nomtrr" parameter from the code.
> 
> --- linux-2.6.22/drivers/video/tdfxfb.c	2007-07-31 11:49:16.921420742 +0200
> +++ linux-2.6.23/drivers/video/tdfxfb.c	2007-07-31 11:49:46.147086218 +0200
> @@ -78,6 +77,24 @@
>  #define DPRINTK(a,b...)
>  #endif
>  
> +#ifdef CONFIG_MTRR
> +#include <asm/mtrr.h>
> +#else
> +/* duplicate asm/mtrr.h defines to work on archs without mtrr */
> +#define MTRR_TYPE_WRCOMB     1
> +
> +static __inline__ int mtrr_add (unsigned long base, unsigned long size,
> +				unsigned int type, char increment)
> +{
> +    return -ENODEV;
> +}
> +static __inline__ int mtrr_del (int reg, unsigned long base,
> +				unsigned long size)
> +{
> +    return -ENODEV;
> +}
> +#endif

While I like your suggestion to move mtrr.h to the include/asm-generic or
include/linux directory, and redefine all functions as dummies in case
CONFIG_MTRR is not defined, the above are not really dummies, as they
return an error code.

> @@ -1227,6 +1246,12 @@ static int __devinit tdfxfb_probe(struct
>  
>  	printk("fb: %s memory = %dK\n", tdfx_fix.id, tdfx_fix.smem_len >> 10);
>  
> +	default_par->mtrr_handle = -1;
> +	if (!nomtrr)
> +		default_par->mtrr_handle =
> +			mtrr_add(tdfx_fix.smem_start, tdfx_fix.smem_len,
> +				 MTRR_TYPE_WRCOMB, 1);
> +

... but everything works nicely, because no callers of mttr_{add,del}()
check for actual errors ;-)

In this case it's a bit tricky to have dummies _and_ check for
failures...

Gr{oetje,eeting}s,

						Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
							    -- Linus Torvalds

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