Re: Bug on atyfb

["Ville Syrjälä" <syrjala@sci.fi>]

On Sat, Dec 11, 2004 at 02:51:42PM -0200, Lucas Correia Villa Real wrote:
> On Friday 10 December 2004 19:19, Antonino A. Daplas wrote:
> > On Saturday 11 December 2004 04:44, Lucas Correia Villa Real wrote:
> > > Hi,
> > >
> > > I'm trying to use atyfb on 2.6.10-rc3, but I'm getting a kernel oops just
> > > at modprobe time. By tracking the problem, it seems that
> > > 'pll_limits.xclk' is the heart of the problem, as seen in line 2210 from
> > > atyfb_base.c:
> > >
> > > par->xclk_per = 1000000/par->pll_limits.xclk;
> > >
> > > It happens that pll_limits.xclk is zero, because of an attribution made
> > > on line 3246:
> > >
> > > par->pll_limits.xclk = pll_block.XCLK_max_freq/100;
> > >
> > > pll_block.XCLK_max_freq, in this case, is read from BIOS a few lines
> > > above (at line 3229, to be more precise), and the value being returned
> > > from this copy here is 20. So we have a problem, since the result from
> > > 20/100 = 0 will be used as denominator to set par->xclk_per's value.
> >
> > Buggy BIOS?  Why not skip the init_from_bios() step, since xclk will be
> > initialized in the function correct_chipset(), just a few lines above?
> >
> > If that works, perhaps a boot option can be added such as no_bios?
> 
> Hi,
> 
> When trying to skip the initialization from bios the driver gets crazy:
> 
> atyfb: using auxiliary register aperture
> atyfb: 3D RAGE II+ (Mach64 GTB) [0x4755 rev 0x9a]
> atyfb: 512K RESV, 14.31818 MHz XTAL, 200 MHz PLL, 67 Mhz MCLK, 67 MHz XCLK
> atyfb: Unsupported xclk source:  5.
> atyfb: vclk out of range
> atyfb: not enough video RAM
> atyfb: not enough video RAM
> atyfb: not enough video RAM
> ...
> atyfb: vclk out of range
> atyfb: can't set default video mode
> ...
> 
> After this broken initialization, if I try to rmmod atyfb, the kernel oops'es. 
> So, I've decided to keep doing the initialization from bios, but if the bios 
> is told to be buggy, correct_from_chipset() is called again to fix some stuff 
> informed by the bios.

Are you saying you don't get these warnings if you call init_from_bios()? 
That sounds really strange as the only thing init_from_bios() does is get 
the PLL limits. So if you call correct_chipset() after init_from_bios() it 
should behave exactly the same as if you didn't call init_from_bios() in 
the first place.

-- 
Ville Syrjälä
syrjala@sci.fi
http://www.sci.fi/~syrjala/


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