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| author |   Krzysztof Helt <krzysztof.h1@wp.pl> | 2007-05-08 00:39:33 -0700 |
|---|---|---|
| committer |   Linus Torvalds <torvalds@woody.linux-foundation.org> | 2007-05-08 11:15:32 -0700 |
| commit | d4a96b53125c3d31266c05f2a8432d956dd26141 (patch) | |
| tree | 5c2dbe527fa673b55d8f2b5f18d6c235cc5d950d /drivers/video/pm2fb.c | |
| parent | pm2fb: Permedia 2V memory clock setting (diff) | |
| download | linux-dev-d4a96b53125c3d31266c05f2a8432d956dd26141.tar.xz linux-dev-d4a96b53125c3d31266c05f2a8432d956dd26141.zip | |
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>
Diffstat (limited to '')
| -rw-r--r-- | drivers/video/pm2fb.c | 6 |
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, 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; |