weird problem...

I just ditched a laptop I was pretty unhappy with (P4HT 3.2Ghz bla bla bla) for a new AMD Turion 64 laptop (1GB RAM). I put Fedora Core 4's x86_64 distribution on it and everything is working fast and fine... except for the time.

By my count, the time on the system is moving 3 seconds for every actual second in "real" time. So for every "real" second that passes I'm getting an extra 2 seconds added on according to the system clock (looking at system-config-time).

I ran a quick test at runlevel 3 and the same thing happens.

Does anyone know of any time complications on x86_64 hardware with Fedora Core 4?
Does anyone know of a fix?

Thanks everyone...
~ Joe

Don't know if this will help you any but I had exactly the same problem when I installed FC3 on my machine - i. e. many seconds (I guess also about 3) passing for each "realtime" second whent he machine was in Linux (I dual boot).

What fixed it was to upgrade the default 2.6.9.something FC3 kernel to the latest 2.6.12 AND to ensure that I had DMA support for my particular chipset compiled into the new kernel. I do not know for sure if it was having DMA that fixed the problem, or just the kernel upgrade from 2.6.9 to 2.6.12, but my system now keeps perfect time with the new kernel AND DMA enabled...

How did you get DMA compiled in?
Is it possible to just grab via yum?

What I did was to experiment a lot to get DMA in - I first had to identify my board's chipset (I have a GA8-TRS350MT fromg Gigabyte which has a IXP300 chipset, according to the manual). I had no idea where to start, but eventually I waded through the 2.6.12 kernel's .config file and found a line that referred to IXP300 which was set to n for no. I set this to Y and recompiled the kernel, installed it and when I booted up again I managed to set DMA for my DVD drives as well as the HDD. BUT I am supposing that also means that other stuff on the mobo was then also using DMA for the first time (like the soundcard, for example.)

I don't know yum, but I generally distrust it and any other "automagic" update thingies - heard of two many guys who broke their systems using things like APT and yum. What you'll probably need to do is to download a kernel manually from kernel.org, unpack, compile and install it. Something like:

1. Unpack the kernel in /usr/src/linux
2. Make clean
3. Make mrproper
4. Make menuconfig (and configure your kernel)
5. Edit the resulting .config in order to set any custom options you want, like I switched on support for the IXP300 chipset)
7. Make all
8. Make modules_install
9. Make install.
10. Reboot

On my FC3 machine, doing it like this also automatically alters my bootloader config so that I can then start the new kernel without further hassle.

Hope this helps!

Thanks a lot!
I'll give it a shot.

I'm sure that digging through the data that came with the laptop or looking online will let me find the chipset for my particular model. I may not get to it for a while (maybe a couple weeks... I am extraordinarily busy for some reason lately), but I will make sure to post the results to this thread when I am done.

Thanks again!

Unfortunately I never found the proper option to turn on. But it's OK, it's not like it bothers me at all. I'll probably give FC5 a shot whenever it comes out and possibly check out Gentoo again around December time.

I just didn't want to leave this post without a reply.

A SOLUTION!!!!!!!!!!!!!!
For those curious... it took a little RTFM


No kernel mods... nothing like that. It's a lot more simple than that.
I opened up my /boot/grub/grub.conf file and...

I changed this line:
To this:

The additions (if you can't see them in there) is the no_timer_check and noapic lines.

I actually found this while looking up some other configurations that I haven't had a chance to play with until now (namely the ndiswrapper, which I have a config error in, but that's a different topic). The no_timer_check actually applies to pretty much any AMD Turion 64 (as far as what I read leads me to believe) and may work for the kernel boot configuration for other distros/systems experiencing similar problems.

Rock on,
The Rev.

This was really helpful for my problem. I have an Asrock 939 dual sata MoBo and an AMD 3800 X2 which under FedoraC4 (32-bit) SMP would gain several seconds per minute. In one hour it had gained 24 minutes and 31 seconds. With the above changes in the grub.conf, it is running within a second of my digital watch after five hours. What is really interesting is that running under the non-SMP kernel it was accurate and when running under Knoppix v4.0.2 DVD as SMP it was accurate. The addition of noapic and no_timer_check to the grub.conf entry for the SMP kernel made the kernel keep time correctly.

Thanks