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authorKrzysztof Helt <krzysztof.h1@wp.pl>2007-05-08 03:39:33 -0400
committerLinus Torvalds <torvalds@woody.linux-foundation.org>2007-05-08 14:15:32 -0400
commitd4a96b53125c3d31266c05f2a8432d956dd26141 (patch)
tree5c2dbe527fa673b55d8f2b5f18d6c235cc5d950d
parente5d809d774fc8aa76899bde3235afb046728feed (diff)
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>
-rw-r--r--drivers/video/pm2fb.c6
1 files changed, 3 insertions, 3 deletions
diff --git a/drivers/video/pm2fb.c b/drivers/video/pm2fb.c
index 6f634e3ae60d..2a8ba6022d3d 100644
--- a/drivers/video/pm2fb.c
+++ b/drivers/video/pm2fb.c
@@ -302,10 +302,10 @@ static void pm2v_mnp(u32 clk, unsigned char* mm, unsigned char* nn,
302 s32 delta = 1000; 302 s32 delta = 1000;
303 303
304 *mm = *nn = *pp = 0; 304 *mm = *nn = *pp = 0;
305 for (n = 1; n; n++) { 305 for ( m = 1; m < 128; m++) {
306 for ( m = 1; m; m++) { 306 for (n = 2 * m + 1; n; n++) {
307 for ( p = 0; p < 2; p++) { 307 for ( p = 0; p < 2; p++) {
308 f = PM2_REFERENCE_CLOCK * n / (m * (1 << (p + 1))); 308 f = ( PM2_REFERENCE_CLOCK >> ( p + 1 )) * n / m;
309 if ( clk > f - delta && clk < f + delta ) { 309 if ( clk > f - delta && clk < f + delta ) {
310 delta = ( clk > f ) ? clk - f : f - clk; 310 delta = ( clk > f ) ? clk - f : f - clk;
311 *mm=m; 311 *mm=m;