[Soekris] SC1100 PCI/TSC BIOS or OS Problem

[Soren Kristensen]

Hi Dave,

Dave wrote:
> Hello all,
> 
> Can anyone confirm whether the TSC and PCI problem on the net4801 is related
> to the BIOS or related to the OS?
> 
> I have had a software provider (MikroTik) inform me that the problem is with
> the net4801 and the BIOS and that they cannot do anything to to fix it in
> the OS.
> 
> Can anyone confirm/deny?

The PCI issue I believe is a pure SC1100 hardware bug that just need a 
simple OS software workaround. I don't believe that it can be fixed in 
the BIOS. It might be fixable using the VSA, but I don't have the VSA 
source code (have asked NSC for it....).

The TSC issue is a SC1100 bug where the TSC stop during autohalt. There 
is two possible workarounds:

1) Disable autohalt using a SC1100 control bit. That way the TSC works, 
but instead the CPU always run using full power. That generates 
unneccesery heat and waste power.

2) Do not use TSC, t.ex. by patching your OS. Instead you can t.ex use 
the 27 Mhz chip counter that PHK so nicely provided a FreeBSD patch for....


I have choosen not to disable the autohalt in the BIOS, as I design low 
power hardware. MikroTik should update their OS to not use the TSC on 
the SC1100 processor.

If enough people think otherwise, I could make a BIOS control knob to 
disable autohalt, but it's really against my principles to do that.


Regards,


Soren