powernow-k8: missing p-state

powernow-k8: missing p-state

[Brendt Wohlberg]

I have an AMD 64 3200+ processor with 4 p-states (according to AMD
specs), with frequencies of 1.0, 1.8, 2.0, and 2.2 GHz. On boot
(Fedora Core 4, kernel 2.6.12), however, the powernow-k8 module only
recognises the highest three frequencies

  powernow-k8: Found 1 AMD Athlon 64 / Opteron processors (version 1.40.2)
  powernow-k8:    0 : fid 0xe (2200 MHz), vid 0x2 (1500 mV)
  powernow-k8:    1 : fid 0xc (2000 MHz), vid 0x6 (1400 mV)
  powernow-k8:    2 : fid 0xa (1800 MHz), vid 0xa (1300 mV)

My guess is that this problem is due to a buggy BIOS. Are there any existing 
solutions to this problem? Given the apparent number of AMD 64 motherboards 
with similar problems, surely it would be useful to be able to specify
the p-state
table as a configuration option for the powernow-k8 module?

Brendt

Re: powernow-k8: missing p-state

[Bruno Ducrot]

On Sun, Aug 07, 2005 at 06:13:46PM -0600, Brendt Wohlberg wrote:
> I have an AMD 64 3200+ processor with 4 p-states (according to AMD
> specs), with frequencies of 1.0, 1.8, 2.0, and 2.2 GHz. On boot
> (Fedora Core 4, kernel 2.6.12), however, the powernow-k8 module only
> recognises the highest three frequencies
> 
>   powernow-k8: Found 1 AMD Athlon 64 / Opteron processors (version 1.40.2)
>   powernow-k8:    0 : fid 0xe (2200 MHz), vid 0x2 (1500 mV)
>   powernow-k8:    1 : fid 0xc (2000 MHz), vid 0x6 (1400 mV)
>   powernow-k8:    2 : fid 0xa (1800 MHz), vid 0xa (1300 mV)
> 
> My guess is that this problem is due to a buggy BIOS. Are there any existing 
> solutions to this problem? Given the apparent number of AMD 64 motherboards 
> with similar problems, surely it would be useful to be able to specify
> the p-state
> table as a configuration option for the powernow-k8 module?

I'm unaware of this problem I'm afraid.

Hi,

Is this with or without ACPI?

Could you send me the output of acpidmp, please ?

wget ftp://ftp.kernel.org//pub/linux/kernel/people/lenb/acpi/utils/pmtools-20031210.tar.bz2
tar xjvfp pmtools-20031210.tar.bz2
cd pmtools-20031210/acpidmp
make
sudo ./acpidmp > acpidmp.out
bzip2 acpidmp.out 

Then mail privately to me the acpidmp.out.bz2

Cheers,

-- 
Bruno Ducrot

--  Which is worse:  ignorance or apathy?
--  Don't know.  Don't care.

RE: powernow-k8: missing p-state

[Langsdorf, Mark]

> I have an AMD 64 3200+ processor with 4 p-states (according 
> to AMD specs), with frequencies of 1.0, 1.8, 2.0, and 2.2 
> GHz. On boot (Fedora Core 4, kernel 2.6.12), however, the 
> powernow-k8 module only recognises the highest three frequencies
> 
>   powernow-k8: Found 1 AMD Athlon 64 / Opteron processors 
> (version 1.40.2)
>   powernow-k8:    0 : fid 0xe (2200 MHz), vid 0x2 (1500 mV)
>   powernow-k8:    1 : fid 0xc (2000 MHz), vid 0x6 (1400 mV)
>   powernow-k8:    2 : fid 0xa (1800 MHz), vid 0xa (1300 mV)
> 
> My guess is that this problem is due to a buggy BIOS. Are 
> there any existing 
> solutions to this problem? Given the apparent number of AMD 
> 64 motherboards 
> with similar problems, surely it would be useful to be able 
> to specify the p-state table as a configuration option for 
> the powernow-k8 module?

It sure would be, and you're welcome to write it.  AMD
corporate policy does not let me distribute the driver 
with that option, nor support people who attempt to 
write that option.

If you look around on the web, you should be able to find
some attempts that other people have made to add that
option.

In the meantime, what motherboard and BIOS are you using?
I can sometimes get BIOS writers to update their BIOSes
if there's a known problem.

-Mark Langsdorf
AMD, Inc.

Re: powernow-k8: missing p-state

[Bruno Ducrot]

[-- Attachment #1: Type: text/plain, Size: 1316 bytes --]

On Mon, Aug 08, 2005 at 09:07:13AM -0600, Brendt Wohlberg wrote:
> Hi Bruno,
> 
> Thanks for your response to my question.
> 
> > > solutions to this problem? Given the apparent number of AMD 64 motherboards 
> > > with similar problems, surely it would be useful to be able to specify
> > > the p-state table as a configuration option for the powernow-k8 module?
> > 
> > I'm unaware of this problem I'm afraid.
> 
> This was an impression I gained from reading reports I found while searching
> the web for a solution; perhaps I've exaggerated the extent of the problem.
> 
> > Is this with or without ACPI?
> 
> The kernel was built with general ACPI support (CONFIG_ACPI=y), as well
> as with the ACPI option for powernow-k8 (CONFIG_X86_POWERNOW_K8_ACPI=y).
>  
> > Could you send me the output of acpidmp, please ?
> 
> With pleasure - it's attached.

As expected, there is only 3 p-states on that one, namely 2200, 2000
and 1800 kHz.

Maybe the legacy tables are not so broken.  Could you please try that
little tool I'm attaching (compile with -O at least)?

NB: it has been written for powernow-k7 originaly.  So it will certainly
give false values.  What I want to see in fact is the number of
frequencies available.

-- 
Bruno Ducrot

--  Which is worse:  ignorance or apathy?
--  Don't know.  Don't care.

[-- Attachment #2: dump_psb_amd64.c --]
[-- Type: text/x-csrc, Size: 2769 bytes --]

#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

#include <sys/mman.h>

#define LEN (0x100000 - 0xc0000)
#define OFFSET (0xc0000)

#ifndef __packed
#define __packed __attribute((packed))
#endif

static const int fid_to_mult[32] = {
	110, 115, 120, 125, 50, 55, 60, 65,
	70, 75, 80, 85, 90, 95, 100, 105,
	30, 190, 40, 200, 130, 135, 140, 210,
	150, 225, 160, 165, 170, 180, -1, -1,
};

static const int vid_to_voltage[32] = {
	2000, 1950, 1900, 1850, 1800, 1750, 1700, 1650,
	1600, 1550, 1500, 1450, 1400, 1350, 1300, 0,
	1275, 1250, 1225, 1200, 1175, 1150, 1125, 1100,
	1075, 1050, 1024, 1000, 975, 950, 925, 0,
}; 

struct psb_header {
	char signature[10];
	u_char version;
	u_char flags;
	u_short settlingtime;
	u_char res1;
	u_char numpst;
} __packed;

struct pst_header {
	u_int32_t cpuid;
	u_char fsb;
	u_char maxfid;
	u_char startvid;
	u_char numpstates;
} __packed;

static u_int fsb;
static u_int sgtc;

static int
decode_pst(char *p, int npstates)
{
	int i;
	int freq, fid, vid;

	for (i = 0; i < npstates; ++i) {
		fid = *p++;
		vid = *p++;
		freq = 100 * fid_to_mult[fid] * fsb;

		printf("   %2d %8dkHz  FID %02x (%2d.%01d)  VID %02x (%4dmV)\n",
		       i,
		       freq,
		       fid, fid_to_mult[fid]/10, fid_to_mult[fid]%10,
		       vid, vid_to_voltage[vid]);
	}

	return 0;
}

static
void decode_psb(char *p, int numpst)
{
	int i;
	struct psb_header *psb;
	struct pst_header *pst;

	psb = (struct psb_header*) p;

	if (psb->version != 0x14)
		return;

	printf("PSB version: %hhx flags: %hhx settling time %hhuus res1 %hhx num pst %hhu\n",
			psb->version,
			psb->flags,
			psb->settlingtime,
			psb->res1,
			psb->numpst);
	sgtc = psb->settlingtime * 100;

	if (sgtc < 10000)
		sgtc = 10000;

	p = ((char *) psb) + sizeof(struct psb_header);

	if (numpst < 0)
		numpst = psb->numpst;
	else
		printf("Overriding number of pst :%d\n", numpst);

	for (i = 0; i < numpst; i++) {
		pst = (struct pst_header*) p;

		printf("  PST %d  cpuid %.3x fsb %hhu mfid %hhx svid %hhx numberstates %hhu\n",
				i+1,
				pst->cpuid,
				pst->fsb,
				pst->maxfid,
				pst->startvid,
				pst->numpstates);

		fsb = pst->fsb;
		decode_pst(p + sizeof(struct pst_header), pst->numpstates);
		p += sizeof(struct pst_header) + 2*pst->numpstates;
	}

}

int
main(int argc, char *argv[])
{
	int fd;
	int numpst;
	char *mem = NULL;
	char *p;

	if (argc < 2)
		numpst = -1;
	else
		numpst = strtoul(argv[1], NULL, 0);

	fd = open("/dev/mem", O_RDONLY);
	if (fd < 0) {
		exit(1);
	}

	mem = mmap(mem, 0x100000 - 0xc0000, PROT_READ, MAP_SHARED, fd, 0xc0000);
	close(fd);

	for (p = mem; p - mem < LEN; p+=16) {
		if (memcmp(p, "AMDK7PNOW!", 10) == 0) {
			decode_psb(p, numpst);
			break;
		}
	}

	munmap(mem, LEN);
	return 0;
}

[-- Attachment #3: Type: text/plain, Size: 147 bytes --]

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RE: powernow-k8: missing p-state

[Langsdorf, Mark]

> > The kernel was built with general ACPI support (CONFIG_ACPI=y), as 
> > well as with the ACPI option for powernow-k8 
> > (CONFIG_X86_POWERNOW_K8_ACPI=y).
> >  
> > > Could you send me the output of acpidmp, please ?
> > 
> > With pleasure - it's attached.
> 
> As expected, there is only 3 p-states on that one, namely 
> 2200, 2000 and 1800 kHz.
> 
> Maybe the legacy tables are not so broken.  Could you please 
> try that little tool I'm attaching (compile with -O at least)?
> 
> NB: it has been written for powernow-k7 originaly.  So it 
> will certainly give false values.  What I want to see in fact 
> is the number of frequencies available.

Bruno -

Thank you for the support, but my experience has been that
the PSB/PST tables are much less likely to exist or be
correct than the ACPI tables.  I'm not sure what your tool
is going to demonstrate.

-Mark Langsdorf
AMD, Inc.

Re: powernow-k8: missing p-state

[Bruno Ducrot]

On Thu, Aug 18, 2005 at 12:24:31PM -0500, Langsdorf, Mark wrote:
> > > The kernel was built with general ACPI support (CONFIG_ACPI=y), as 
> > > well as with the ACPI option for powernow-k8 
> > > (CONFIG_X86_POWERNOW_K8_ACPI=y).
> > >  
> > > > Could you send me the output of acpidmp, please ?
> > > 
> > > With pleasure - it's attached.
> > 
> > As expected, there is only 3 p-states on that one, namely 
> > 2200, 2000 and 1800 kHz.
> > 
> > Maybe the legacy tables are not so broken.  Could you please 
> > try that little tool I'm attaching (compile with -O at least)?
> > 
> > NB: it has been written for powernow-k7 originaly.  So it 
> > will certainly give false values.  What I want to see in fact 
> > is the number of frequencies available.
> 
> Bruno -
> 
> Thank you for the support, but my experience has been that
> the PSB/PST tables are much less likely to exist or be
> correct than the ACPI tables.  I'm not sure what your tool
> is going to demonstrate.
> 

I want to demonstrate nothing.  But if for *one* guy it's better
to use PSB/PST tables instead of those provided by ACPI, then
a kernel boot parameter in order to force the use of those
tables should be written IMHO.

It's not the case here, therefore I won't bother to write
such a patch.

Cheers,

-- 
Bruno Ducrot

--  Which is worse:  ignorance or apathy?
--  Don't know.  Don't care.