Re: atyfb - system hangs at bootup prior to enabling framebuffer console -- linux 2.6.18

On Sat, Feb 17, 2007 at 08:19:12AM EST, Ville Syrjälä wrote:
> On Fri, Feb 16, 2007 at 06:37:31PM -0500, cga2000 wrote:
> > More than 50% of the time my laptop hangs when booting with 
> > 
> > ... video=atyfb:1400x1050.
> > 
> > I have seen similar occurrences reported here and there with recent 2.6
> > kernels but nothing very clear as to whether this is a known problem or
> > whether a patch or workaround has already been provided.
> 
> I was just able to reproduce the problem by switching from drivers/ide 
> to libata. In my case the laptop would hang on every boot. Apparently 
> using libata changed the timing enough to trigger the bug.
> 
> Try this patch:
> 
> ---
>  drivers/video/aty/mach64_ct.c |    9 +++------
>  1 file changed, 3 insertions(+), 6 deletions(-)
> 
> Index: linux-2.6.20/drivers/video/aty/mach64_ct.c
> ===================================================================
> --- linux-2.6.20.orig/drivers/video/aty/mach64_ct.c
> +++ linux-2.6.20/drivers/video/aty/mach64_ct.c
> @@ -598,7 +598,6 @@ static void aty_resume_pll_ct(const stru
>  	struct atyfb_par *par = info->par;
>  
>  	if (par->mclk_per != par->xclk_per) {
> -		int i;
>  		/*
>  		* This disables the sclk, crashes the computer as reported:
>  		* aty_st_pll_ct(SPLL_CNTL2, 3, info);
> @@ -609,12 +608,10 @@ static void aty_resume_pll_ct(const stru
>  		aty_st_pll_ct(SCLK_FB_DIV, pll->ct.sclk_fb_div, par);
>  		aty_st_pll_ct(SPLL_CNTL2, pll->ct.spll_cntl2, par);
>  		/*
> -		 * The sclk has been started. However, I believe the first clock
> -		 * ticks it generates are not very stable. Hope this primitive loop
> -		 * helps for Rage Mobilities that sometimes crash when
> -		 * we switch to sclk. (Daniel Mantione, 13-05-2003)
> +		 * The sclk has been started. Wait for the PLL to lock. 5 ms
> +		 * should be enough according to mach64 programmers guide.
>  		 */
> -		for (i=0;i<=0x1ffff;i++);
> +		mdelay(5);
>  	}
>  
>  	aty_st_pll_ct(PLL_REF_DIV, pll->ct.pll_ref_div, par);

Thanks.

I was planning on streamlining my new 2.6.18 kernel over the weekend so
I should be able to report back to you by Monday.

cga.

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