NS Geode: Is it OK to enable TSC [2.4.x]

NS Geode: Is it OK to enable TSC [2.4.x]

[Herman Theron]

Hi everyone,

I'm running a SBC computer with a NS Geode GX1-233 processor.
Normallly, you can only compile the kernel with the CONFIG_M586 option.
Doing some experimentation, I enabled the TSC in the file:
/usr/src/linux/arch/i386/kernel/setup.c (by commenting out the
"clear_bit(X86_FEATURE_TSC...." for the GX processor in the function
"init_cyrix". I then compiled the kernel then with CONFIG_M586MMX. So
far the system is running non-stop (without any apparent problems) for
24 hours with a RTAI-application aswell.

This is the info I get from 'cat /proc/cpuinfo'
processor	: 0
vendor_id	: CyrixInstead
cpu family	: 5
model		: 9
model name	: Geode(TM) Integrated Processor by National Semi
stepping	: 1
cpu MHz		: 232.742
cache size	: 16 KB
fdiv_bug	: no
hlt_bug		: no
f00f_bug	: no
coma_bug	: no
fpu		: yes
fpu_exception	: yes
cpuid level	: 2
wp		: yes
flags		: fpu tsc msr cx8 cmov mmx cxmmx
bogomips	: 463.66

Is there any test that I can do to make sure it works OK? And if so,
can the kernel then be modified to reflect this?

Thanks for any info
Herman

****************************************
Herman Theron
Hermanus Magnetic Observatory
CSIR
PO Box 32
Hermanus
7200
South Africa
E-mail: hetheron@csir.co.za
Phone: +27 28 3121196
Fax: +27 28 3122039
Cel: +27 833 206 311

Re: NS Geode: Is it OK to enable TSC [2.4.x]

[Alan Cox]

> Normallly, you can only compile the kernel with the CONFIG_M586 option.
> Doing some experimentation, I enabled the TSC in the file:
> /usr/src/linux/arch/i386/kernel/setup.c (by commenting out the
> "clear_bit(X86_FEATURE_TSC...." for the GX processor in the function
> "init_cyrix". I then compiled the kernel then with CONFIG_M586MMX. So
> far the system is running non-stop (without any apparent problems) for
> 24 hours with a RTAI-application aswell.

Certain combinations of Geode/MediaGX and chipset fail because of problems
with the emulation of the pc timers. If your machine even boots without
a panic about that or hanging then its not afflicted. Someone sent a work
around for this problem to the kenrel list recently and its on my pile
of things to tidy up and merge.