Commit d4a96b53 authored May 08, 2007 by Krzysztof Helt Committed by Linus Torvalds May 08, 2007

pm2fb: pixclock setting restriction



This patch adds restrictions to calculations of m, n and p factors
which sets the pixclock for the Permedia 2V. I found during tests
that synchronization is unstable if m (divisor) is bigger than
half of the n (numerator). The patch disallows such settings
combination.

Signed-off-by: Krzysztof Helt <krzysztof.h1@wp.pl>
Signed-off-by: Antonino Daplas <adaplas@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent e5d809d7

drivers/video/pm2fb.c

+3 −3

Original line number	Diff line number	Diff line
		@@ -302,10 +302,10 @@ static void pm2v_mnp(u32 clk, unsigned char* mm, unsigned char* nn,
		s32 delta = 1000;

		mm = nn = *pp = 0;
		for (n = 1; n; n++) {
		for ( m = 1; m; m++) {
		for ( m = 1; m < 128; m++) {
		for (n = 2 * m + 1; n; n++) {
		for ( p = 0; p < 2; p++) {
		f = PM2_REFERENCE_CLOCK * n / (m * (1 << (p + 1)));
		f = ( PM2_REFERENCE_CLOCK >> ( p + 1 )) * n / m;
		if ( clk > f - delta && clk < f + delta ) {
		delta = ( clk > f ) ? clk - f : f - clk;
		*mm=m;

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