linux-kernel - Re: [PATCH] fbdev: matrox: make array wtst_xlat static const, makes object smaller

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Date:   Fri, 6 Sep 2019 21:17:14 +0300
From:   Ville Syrjälä <ville.syrjala@...ux.intel.com>
To:     Colin King <colin.king@...onical.com>
Cc:     Bartlomiej Zolnierkiewicz <b.zolnierkie@...sung.com>,
        linux-fbdev@...r.kernel.org, dri-devel@...ts.freedesktop.org,
        kernel-janitors@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] fbdev: matrox: make array wtst_xlat static const, makes
 object smaller

On Fri, Sep 06, 2019 at 07:11:14PM +0100, Colin King wrote:
> From: Colin Ian King <colin.king@...onical.com>
> 
> Don't populate the array wtst_xlat on the stack but instead make it
> static const. Makes the object code smaller by 89 bytes.
> 
> Before:
>    text	   data	    bss	    dec	    hex	filename
>   14347	    840	      0	  15187	   3b53	fbdev/matrox/matroxfb_misc.o
> 
> After:
>    text	   data	    bss	    dec	    hex	filename
>   14162	    936	      0	  15098	   3afa	fbdev/matrox/matroxfb_misc.o
> 
> (gcc version 9.2.1, amd64)
> 
> Signed-off-by: Colin Ian King <colin.king@...onical.com>
> ---
>  drivers/video/fbdev/matrox/matroxfb_misc.c | 5 ++++-
>  1 file changed, 4 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/video/fbdev/matrox/matroxfb_misc.c b/drivers/video/fbdev/matrox/matroxfb_misc.c
> index c7aaca12805e..feb0977c82eb 100644
> --- a/drivers/video/fbdev/matrox/matroxfb_misc.c
> +++ b/drivers/video/fbdev/matrox/matroxfb_misc.c
> @@ -673,7 +673,10 @@ static int parse_pins5(struct matrox_fb_info *minfo,
>  	if (bd->pins[115] & 4) {
>  		minfo->values.reg.mctlwtst_core = minfo->values.reg.mctlwtst;
>  	} else {
> -		u_int32_t wtst_xlat[] = { 0, 1, 5, 6, 7, 5, 2, 3 };
> +		static const u_int32_t wtst_xlat[] = {
> +			0, 1, 5, 6, 7, 5, 2, 3

All of those would easily fit in u8 as well.

> +		};
> +
>  		minfo->values.reg.mctlwtst_core = (minfo->values.reg.mctlwtst & ~7) |
>  						  wtst_xlat[minfo->values.reg.mctlwtst & 7];
>  	}
> -- 
> 2.20.1
> 
> _______________________________________________
> dri-devel mailing list
> dri-devel@...ts.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/dri-devel

-- 
Ville Syrjälä
Intel

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