Messages in this thread Patch in this message | | | Date | Fri, 23 Jan 2009 15:21:51 +0100 | From | Mikael Pettersson <> | Subject | Re: [PATCH] atyfb: fix distorted image on PowerMacs |
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Risto Suominen writes: > Since the complete re-write in 2.6.10, some PowerMacs (At least PowerMac 5500 > and PowerMac G3 Beige rev A) with ATI Mach64 chip have suffered from unstable > columns in their framebuffer image. This seems to depend on a value (4) read > from PLL_EXT_CNTL register, which leads to incorrect DSP config parameters to > be written to the chip. This patch uses a value calculated by aty_init_pll_ct > instead, as a starting point. > > Signed-off-by: Risto Suominen <Risto.Suominen@gmail.com>
Thank you. I reported this issue way back in March 2005 <http://marc.info/?l=linux-kernel&m=111175371705665&w=2> but nothing ever came out of that. Your patch applies cleanly to 2.6.29-rc2 and fixes the issue on my Beige G3.
Tested-by: Mikael Pettersson <mikpe@it.uu.se>
> --- > The testing is done on kernel version 2.6.18. > > --- a/drivers/video/aty/mach64_ct.c.org 2006-09-20 06:42:06.000000000 +0300 > +++ b/drivers/video/aty/mach64_ct.c 2009-01-22 14:28:13.000000000 +0200 > @@ -7,6 +7,7 @@ > #include <linux/delay.h> > #include <asm/io.h> > #include <video/mach64.h> > +#include <asm/machdep.h> > #include "atyfb.h" > #undef DEBUG > @@ -536,6 +537,14 @@ static int __init aty_init_pll_ct(const > pll->ct.xclk_post_div_real = postdividers[xpost_div]; > pll->ct.mclk_fb_div = q * pll->ct.xclk_post_div_real / 8; > > +#ifdef CONFIG_PPC > + if (machine_is(powermac)) { > + /* Override PLL_EXT_CNTL & 0x07. */ > + pll->ct.xclk_post_div = xpost_div; > + pll->ct.xclk_ref_div = 1; > + } > +#endif > + > #ifdef DEBUG > pllmclk = (1000000 * pll->ct.mclk_fb_mult * pll->ct.mclk_fb_div) / > (par->ref_clk_per * pll->ct.pll_ref_div); > Since the complete re-write in 2.6.10, some PowerMacs (At least PowerMac 5500 > and PowerMac G3 Beige rev A) with ATI Mach64 chip have suffered from unstable > columns in their framebuffer image. This seems to depend on a value (4) read > from PLL_EXT_CNTL register, which leads to incorrect DSP config parameters to > be written to the chip. This patch uses a value calculated by aty_init_pll_ct > instead, as a starting point. > > Signed-off-by: Risto Suominen <Risto.Suominen@gmail.com> > --- > The testing is done on kernel version 2.6.18. > > --- a/drivers/video/aty/mach64_ct.c.org 2006-09-20 06:42:06.000000000 +0300 > +++ b/drivers/video/aty/mach64_ct.c 2009-01-22 14:28:13.000000000 +0200 > @@ -7,6 +7,7 @@ > #include <linux/delay.h> > #include <asm/io.h> > #include <video/mach64.h> > +#include <asm/machdep.h> > #include "atyfb.h" > > #undef DEBUG > @@ -536,6 +537,14 @@ static int __init aty_init_pll_ct(const > pll->ct.xclk_post_div_real = postdividers[xpost_div]; > pll->ct.mclk_fb_div = q * pll->ct.xclk_post_div_real / 8; > > +#ifdef CONFIG_PPC > + if (machine_is(powermac)) { > + /* Override PLL_EXT_CNTL & 0x07. */ > + pll->ct.xclk_post_div = xpost_div; > + pll->ct.xclk_ref_div = 1; > + } > +#endif > + > #ifdef DEBUG > pllmclk = (1000000 * pll->ct.mclk_fb_mult * pll->ct.mclk_fb_div) / > (par->ref_clk_per * pll->ct.pll_ref_div);
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