From: Paul A. Clarke I wish I was happier about this patch. It'll serve as a placeholder for the moment. I'm still trying to get a G550 working in order to even reproduce the problem this patch introduces. I find that the G450 has jitter even without this patch, so it won't show me what the patch changed. At this point, I'll continue trying to get the G550 to work, and in parallel work with the G450 to work out the kinks. The patch is below. Set XDVICLKCTRL only on PPC, as doing this apparently introduces jitter on the G550, at least on x86 architectures. Signed-off-by: Paul A. Clarke Signed-off-by: Petr Vandrovec Cc: "Antonino A. Daplas" Signed-off-by: Andrew Morton --- drivers/video/matrox/g450_pll.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff -puN drivers/video/matrox/g450_pll.c~matroxfb-fix-jittery-display-on-non-ppc-systems drivers/video/matrox/g450_pll.c --- a/drivers/video/matrox/g450_pll.c~matroxfb-fix-jittery-display-on-non-ppc-systems +++ a/drivers/video/matrox/g450_pll.c @@ -331,7 +331,15 @@ static int __g450_setclk(WPMINFO unsigne tmp |= M1064_XPIXCLKCTRL_PLL_UP; } matroxfb_DAC_out(PMINFO M1064_XPIXCLKCTRL, tmp); +#ifdef __powerpc__ + /* This is necessary to avoid jitter on PowerPC + * (OpenFirmware) systems, but apparently + * introduces jitter, at least on a x86-64 + * using DVI. + * A simple workaround is disable for non-PPC. + */ matroxfb_DAC_out(PMINFO M1064_XDVICLKCTRL, 0); +#endif /* __powerpc__ */ matroxfb_DAC_out(PMINFO M1064_XPWRCTRL, xpwrctrl); matroxfb_DAC_unlock_irqrestore(flags); _