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sunem

8 Posts

15434

October 19th, 2006 17:00

Speedstep not enabled in bios

Hi all.

Speedstep has stopped working in Linux, and acpidump shows no support for this in the bios. Neither are there any relevant options in bios setup.

Now, you may not support Linux (if you do, however, great :-)), but I am told that windows 2000 is also dependent on bios support for enabling this feature, so it would be nice to see it in there.

I have tested bios versions A08 and A09 and found nothing in either.

Best regards,

Sune Mølgaard
Denmark

NemesisDB

2 Intern

 • 

7.9K Posts

October 20th, 2006 16:00

generally only lattitude bioses are validated for w2k. all this said, if someone can solve your problem they're going to need to know what model of computer you have.

sunem

8 Posts

October 20th, 2006 20:00

My initial conclusion may have been faulty afterall, but that something is amiss remains. For the interested, I have had some correspondence on the linux-acpi mailing list (http://marc.theaimsgroup.com/?l=linux-acpi&r=1&w=2) and am currently testing some things under the private mail advice of Venkatesh Pallipadi. If we come to the conclusion that something really is amiss in the bios, I will report back.

The exact model is Inspiron 6000, BIOS version A09.

Best regards,

Sune Mølgaard

sunem

8 Posts

October 24th, 2006 17:00

Looks like the bios isn't sending all the ACPI info it should to the OS, from what Mr. Pallipadi tells me. Now I have invited him to do a more thorough explanation of what seems to be the problem, so I expect a post from him shortly.

Best regards,

Sune Mølgaard

Venki Pallipadi

1 Message

October 26th, 2006 16:00

I guess something changed in this BIOS recently...
 
 
This is how Linux ACPI handles speedstep.
 
- It writes to ACPI _PDC the value of 0x2b
- Tries to read ACPI _PCT back.
 
Right now it is not able to find _PCT on this platform.
 
With ACPI disassembly of BIOS SSDT, this what I see 
        Method (_PDC, 1, NotSerialized)
        {
            CreateDWordField (Arg0, 0x08, CAP0)
            Store (CAP0, PDC0)
            If (LAnd (And (CFGD, 0x4000), LEqual (And (PDC0, 0x0A
                ), 0x0A)))
            {
                If (And (CFGD, 0x03))
                {
                    OperationRegion (IST0, SystemMemory, DerefOf (Index (SSDT, 0x01)), DerefOf (Index (SSDT, 0x02
                        )))
                    Load (IST0, HI0)
                }

                If (And (CFGD, 0x10))
                {
                    OperationRegion (CST0, SystemMemory, DerefOf (Index (SSDT, 0x07)), DerefOf (Index (SSDT, 0x08
                        )))
                    Load (CST0, HC0)
                }
            }
 
 
        }
    }
 
 
And CST0, IST0 defined as
 
 
 
 
        Name (SSDT, Package (0x0C)
        {
            "CPU0IST ", 
            0x00000000, 
            0x4F7F9B70, 
            "CPU1IST ", 
            0x00000000, 
            0x4F7F9B70, 
            "CPU0CST ", 
            0x4F7D465C, 
            0x000001D8, 
            "CPU1CST ", 
            0x00000000, 
            0x4F7F9B70
        })
 
 
 
 
 
So, inspite of proper _PDC, somehow CPU0CST is not getting loaded, looks like. My suspicion is CFGD value is changed. Can anyone from Dell please comment on CFGD value for this platform and why it is not loading CST0 in this case.
 
 
 
 
 
Thanks,
 
 
Venki
 

sunem
8 Posts
June 21st, 2007 08:00
Thought I'd bump this, as Dell seems to have warmed a little to Linux. 

 

Any ideas?
sunem
8 Posts
July 16th, 2007 18:00
Btw., there are a number of other, more trivial, errors in this bios that would, none the less, be nice to have solved by Dell themselves. Where does one report this? /sunem
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