Is a SL8U6 (PM 745 with C0 stepping) usable in T42?

[Johan]

Does anybody know (for sure, and without relying on assuptions or beliefs, please!) if a SL8U6 CPU, which is a Pentium Mobile 745 having a C0 stepping, is usable in T42? The T42 in question has the newest Embedded Controller, ver. 1RHT71WW (3.04) and the newest BIOS ver. 1RETDRWW (3.23). Brief specs for the SL8U6 is found in List of Intel Pentium M microprocessors.

Reason for asking this question is that there are a number of contradictory claims about the possibility to use a ”C0”-stepping Dothan in T4x’s, where some claim this to be possible; e.g. in the thread:

Check it to be sure, but:

SL7V3, SL7UZ, SL7EM, SL7EL, SL8QZ, SL8U6, SL7EN, SL8U8.

You need the 400 MT/s cards. Stepping doesn't matter.

...whereas others claim this to be impossible:

You also need to ensure you get a B stepping chip. The C stepping chips do not work at full speed. You want 400MT/s Front side bus for your T40.

and...:

My EC is up to date. However, regarding T40-T41-T42 & some R50-R51, I don't think this EC version supports C stepping CPU's..

On a Polish site Pentium M 1.8 Ghz Chodzi Tylko Na 600mhz, W IBM T42 and using a Free Polish online translator I get the impression that it is there claimed not to be possible to use the SL8U6 in a T42?

In the Personal Systems Reference - Intel PC Processors – withdrawn, December 2007 - Version 332 nothing is mentioned about stepping. I cannot find any information about usable CPU-stepping in ThinkPad's elsewhere IBM's site...

So, what is the truth; will a C0-stepping Dothan, such as the SL8U6, work in a T42 (at full speed!), or won't it?? Thanks in advance for any help to clear up my confusion!

Best regards,

Johan

[aaa]

I'm using a C0 dothan right now in my T40. You need to mess around to get it to work faster than 600, with either NHC or RMClock.

There is a thread on this btw, and somebody actually did have a 745a, and another person had a 735a.

[Johan]

Thanks very much, aaa, for this specific information!

Would you (or anybody else?) happen to know exatly what it is necessary to "mess with", and where this "messing" must/can be done? I am quite familiar with NHC, which I would prefer to keep using (and I am also not certain, here on the fly, if NHC and RMClock will work together/simultaneously?).

If you happen to recall the thread mentioned ("somebody actually did have a 745a, and another person had a 735a"), I would be very interested in a link!

Thanks, again - it is a bit confusing with so many different messages, some saying: "Yes, you can!" and others: "No, you cannot!" (use stepping-C0 Dothans in T4x's)...

Best regards,

Johan

[aaa]

http://forum.thinkpads.com/viewtopic.ph ... ight=sl89u

No idea what exactly you have to do in Windows, as I only did it on Linux. I just heard somebody got it working.

[sktn77a]

The "A" suffix CPUs don't run at full speed in the T40/41/42 and the 533 FSB CPUs (obviously) run 20% slower. I believe the "A" suffix chips are the C0 stepping models you refer to.

[Johan]

I believe the "A" suffix chips are the C0 stepping models you refer to.

Who are the "you" here - aaa or me (Johan)? What I (Johan!) refer to is the SL8U6 which is a Pentium M 745, hence without the "A" suffix.

Yesterday a bunch of brand-new SL8U6's went for around $40 on eBay, but I didn't dare bid, since I have still not been convinced if the SL8U6 is usable in a T42 or not - so anyone knowing (knowing!) this - please step forward!

Johan

[joerenes]

I can confirm that a SL8QZ "works" in a t41p, by which I mean:

1. up to date bios 3.23 and ecu 3.04 shows cpu as 1.57 GHz (should be 1.

2. under windows, nhc is able to clock the processor to 1.8 GHz as advertised. enable advanced options and then change settings in the CPU Speed tab

3. under linux (ubuntu 7.10) I could not enable speedstep. I was hoping to modify the speedstep-centrino.c file as aaa suggested http://forum.thinkpads.com/viewtopic.ph ... ight=sl89u but the version of the file I got from the ubuntu kernel source package didn't have the section indicated. Instead, I tried building new cpufreq modules as shown here: https://www.dedigentoo.org/trac/linux-p ... ubuntu_001 but still no luck. modprobe acpi-cpufreq fails with "No such device" as here: https://bugs.launchpad.net/ubuntu/+sour ... bug/120759

Easiest fix for me is to get a SL7EN...

[aaa]

Here is the source I'm using:
http://pastebin.com/f660d02dc

It seems to be patched with PHC, but I do not use that (it wasn't working with that particular file? I don't remember why I stopped). Instead, I hardcoded the voltages under the "1501" entry.

So first you need to know how to compile it properly, making sure you use the Ubuntu kernel config (in /boot) so the module will be compatible.

Then you'd copy the cpufreq_frequency_table dothan_1800 table, and rename the new copy to cpufreq_frequency_table dothan_1801 or something, and put your voltages in.

Then you'd add your new table to the list of compatible CPUs. Here you can see my 1501 entry using the C0 id code insted of B0:

Code: Select all

#
#ifdef CONFIG_X86_SPEEDSTEP_CENTRINO_BUILTIN_DOTHAN
        /* Builtin tables for Dothan B0 CPUs */
        DOTHAN(&cpu_ids[CPU_DOTHAN_B0], 1100, "1.10"),
        DOTHAN(&cpu_ids[CPU_DOTHAN_B0], 1400, "1.40"),
        DOTHAN(&cpu_ids[CPU_DOTHAN_B0], 1500, "1.50"),
        DOTHAN(&cpu_ids[CPU_DOTHAN_C0], 1501, "1.50"),
        DOTHAN(&cpu_ids[CPU_DOTHAN_B0], 1600, "1.60"),
        DOTHAN(&cpu_ids[CPU_DOTHAN_B0], 1700, "1.70"),
        DOTHAN(&cpu_ids[CPU_DOTHAN_B0], 1800, "1.80"),
        DOTHAN(&cpu_ids[CPU_DOTHAN_B0], 2000, "2.00"),
#endif /* CONFIG_X86_SPEEDSTEP_CENTRINO_BUILTIN_DOTHAN */

So 1501 is the id of the table you created (as opposed to 1500 which is the default not-undervolted table). And pay attention to the "1.50" string, it has to match the name hardcoded in the CPU exactly (sometimes it says 1500MHz instead of 1.50GHz, check /proc/cpuinfo).

[joerenes]

Success! Thanks aaa. You're right, I needed to apply your changes *after* the phc patch...

In case anyone else has this problem, here's what I did:
1. get ubuntu gutsy gibbon kernel source (2.6.22)
2. apply the phc patch following directions here: https://www.dedigentoo.org/trac/linux-p ... ubuntu_001 (the vanilla kernel patch seems to work fine.)
3. apply the changes given by aaa above
4. finish the steps given in 2, building and installing the modules.
5. reboot.

I guess similar changes can be made for more up-to-date kernels, but I'm leaving that and undervolting the cpu for another day...