Re: powernow-k7: wrong FSB frequency detection

From: Sergey Vlasov <vsu@altlinux.ru>
To: Bruno Ducrot <ducrot@poupinou.org>
Cc: cpufreq@www.linux.org.uk
Subject: Re: powernow-k7: wrong FSB frequency detection
Date: Fri, 2 Jul 2004 19:34:56 +0400	[thread overview]
Message-ID: <20040702153456.GD17160@master.mivlgu.local> (raw)
In-Reply-To: <20040701180215.GH5614@poupinou.org>

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On Thu, Jul 01, 2004 at 08:02:15PM +0200, Bruno Ducrot wrote:
> > > Could you please try this little debug stuff ?  That will not help for
> > > now, but I want to be sure.
> > 
> 
> Thanks.  IMHO we should restore the old behaviour, that is using the
> max fid as per powernow spec, then provide something for people who
> unfortunately do have borken bios (those who put the processor not in
> max fid before booting OS).
> 
> Dave, could you please apply this patch?  I will provide the workaround
> for the unfortunate tomorow, after searching who do have the borken
> bios, and probably yet another powernow boot option :(
> 
> --- linux-2.6/arch/i386/kernel/cpu/cpufreq/powernow-k7.c	2004/07/01 15:01:46	1.1
> +++ linux-2.6/arch/i386/kernel/cpu/cpufreq/powernow-k7.c	2004/07/01 17:56:12
> @@ -565,7 +565,7 @@ static int __init powernow_cpu_init (str
>  	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.CFID];
> +	fsb = (10 * cpu_khz) / fid_codes[fidvidstatus.bits.MFID];
>  	if (!fsb) {
>  		printk(KERN_WARNING PFX "can not determine bus frequency\n");
>  		return -EINVAL;
> 
> -- 

With this patch the results are much better:

powernow: PowerNOW! Technology present. Can scale: frequency and voltage.
powernow: FSB: 133.374 MHz
powernow: Found PSB header at c00f1960
powernow: Table version: 0x12
powernow: Flags: 0x0 (Mobile voltage regulator)
powernow: Settling Time: 100 microseconds.
powernow: Has 1 PST tables. (Only dumping ones relevant to this CPU).
powernow: No PST tables match this cpuid (0x7a0)
powernow: This is indicative of a broken BIOS.
powernow: Trying ACPI perflib
powernow: acpi:  P0: 1867 MHz 24000 mW 125 uS control 009c4176 SGTC 10000
powernow:    FID: 0x16 (14.0x [1867MHz])        VID: 0xb (1.450V)
powernow: acpi:  P1: 1400 MHz 14486 mW 125 uS control 009c41cf SGTC 10000
powernow:    FID: 0xf (10.5x [1400MHz]) VID: 0xe (1.300V)
powernow: acpi:  P2: 1200 MHz 14486 mW 125 uS control 009c41cc SGTC 10000
powernow:    FID: 0xc (9.0x [1200MHz])  VID: 0xe (1.300V)
powernow: acpi:  P3: 1067 MHz 14486 mW 125 uS control 009c426a SGTC 10000
powernow:    FID: 0xa (8.0x [1066MHz])  VID: 0x13 (1.200V)
powernow: acpi:  P4: 933 MHz 14486 mW 125 uS control 009c4268 SGTC 10000
powernow:    FID: 0x8 (7.0x [933MHz])   VID: 0x13 (1.200V)
powernow: acpi:  P5: 668 MHz 14486 mW 125 uS control 009c42e4 SGTC 10000
powernow:    FID: 0x4 (5.0x [666MHz])   VID: 0x17 (1.100V)
powernow: Minimum speed 666 MHz. Maximum speed 1867 MHz.

# cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_available_frequencies 
1867236 1400427 1200366 1066992 933618 666870 

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