Re: cx88-dsp.c: missing =?utf-8?b?X19kaXZkaTM=?= on 32bit kernel

Commit Message

Marton Balint April 8, 2009, 8:36 p.m. UTC

On Tue, 7 Apr 2009, Marton Balint wrote:
> On Mon, 6 Apr 2009, Miroslav Å ustek wrote:
> 
> > Well this patch should solve it.
> > 
> > I don't know how many samples are processed so:
> > First patch is for situation when N*N fits in s32.
> > Second one uses two divisions, but doesn't have any abnormal restrictions for N.
> 
> Both patches are fine, beacuse in the current implementation N is not 
> bigger than 576. Thanks for fixing this problem.

It seems that an #include is missing to math64.h. Below is a patch that 
adds the missing include.

Regards,
   Marton

# HG changeset patch
# User Marton Balint <[e-mail]>
# Date 1239222228 -7200
# Node ID c07293f1b5e44a8614f8f84c6b4fc586a02e69eb
# Parent  202a1c7ec37968f35678980b5f3d9812e5961ef0
cx88: dsp: add missing include to math64.h

From: Marton Balint <[e-mail]>

This patch adds a missing include to math64.h and replaces div_s64_rem with
div_s64 since the remainder is not used anyway.

Priority: normal

Signed-off-by: Marton Balint <[e-mail]>

Patch

diff -r 202a1c7ec379 -r c07293f1b5e4 linux/drivers/media/video/cx88/cx88-dsp.c
--- a/linux/drivers/media/video/cx88/cx88-dsp.c	Mon Apr 06 23:07:04 2009 +0000
+++ b/linux/drivers/media/video/cx88/cx88-dsp.c	Wed Apr 08 22:23:48 2009 +0200
@@ -22,6 +22,7 @@ 
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/jiffies.h>
+#include <linux/math64.h>
 
 #include "cx88.h"
 #include "cx88-reg.h"
@@ -100,9 +101,7 @@ 
 	s32 s_prev2 = 0;
 	s32 coeff = 2*int_cos(freq);
 	u32 i;
-
 	s64 tmp;
-	u32 remainder;
 
 	for (i = 0; i < N; i++) {
 		s32 s = x[i] + ((s64)coeff*s_prev/32768) - s_prev2;
@@ -113,9 +112,8 @@ 
 	tmp = (s64)s_prev2*s_prev2 + (s64)s_prev*s_prev -
 		      (s64)coeff*s_prev2*s_prev/32768;
 
-	/* XXX: N must be low enough so that N*N fits in s32.
-	 * Else we need two divisions. */
-	return (u32) div_s64_rem(tmp, N*N, &remainder);
+	/* N is low enough so N*N fits in s32. */
+	return (u32) div_s64(tmp, N*N);
 }
 
 static u32 freq_magnitude(s16 x[], u32 N, u32 freq)