Re: [Bug 3600] New: Cpu recognization fails after upgrade from 2.6.7 to 2.6.9

[Kronos <kronos@kronoz.cjb.net>]

Il Thu, Oct 21, 2004 at 12:25:29PM +0200, Bruno Ducrot ha scritto: 
> On Wed, Oct 20, 2004 at 06:51:10PM +0200, Kronos wrote:
> > Il Wed, Oct 20, 2004 at 06:05:37PM +0200, Daniele Bonomi ha scritto: 
> > > On Wed, 20 Oct 2004 17:47:44 +0200 Kronos <kronos@kronoz.cjb.net> wrote:
> > > 
> > > > Hi,
> > > > I saw something similar on my notebook. In my case when the notebook
> > > > is turned on while using battery BIOS sets CPU speed to a frequency
> > > > lower than the defaul (800MHz for me). It seems that powernow driver
> > > > is confused by the BIOS fiddling with CPU speed and fails to load. I
> > > > had the same symptoms: PST not found and wrong min/max frequencies.
> > > > 
> > > > Disabling "Automatic CPU power saving" (or something like that) in the
> > > > BIOS cures the problem for me. Note that this option do not affect
> > > > power management under linux (or windows), it just controls the CPU
> > > > before a real OS comes up.
> > > 
> > > I tried but it didn't worked for me.
> > > For me doesn't work even if i'm plugged in...
> > 
> > Ok, can you apply this patch to 2.6.9 (and enable debug):
> > 
> > --- a/arch/i386/kernel/cpu/cpufreq/powernow-k7.c	2004-10-20 18:46:51.000000000 +0200
> > +++ b/arch/i386/kernel/cpu/cpufreq/powernow-k7.c	2004-10-20 18:47:06.000000000 +0200
> > @@ -597,7 +597,7 @@
> >  	rdmsrl (MSR_K7_FID_VID_STATUS, fidvidstatus.val);
> >  
> >  	/* A K7 with powernow technology is set to max frequency by BIOS */
> > -	fsb = (10 * cpu_khz) / fid_codes[fidvidstatus.bits.MFID];
> > +	fsb = (10 * cpu_khz) / fid_codes[fidvidstatus.bits.CFID];
> >  	if (!fsb) {
> >  		printk(KERN_WARNING PFX "can not determine bus frequency\n");
> >  		return -EINVAL;
> > 
> > 
> 
> No.  It's wrong.  Though I *much* prefer the form you submit, this will
> break other unfortunately, and therefore maxfid have to be used
> here for now as per AMD documentation (problem is, your bios is broken
> because it do not respect AMD recomandation since after POST the
> processor shall be put in max frequencies instead of 800MHz). 

Yes I know, I was trying to pin down the problem. I was almost sure that
the BIOS was changing frequency since I had the same problem, though in
my case I was able to teach the BIOS to not touch the CPU.

Luca
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