kernel 2.6.23-rc6 hangs on Geode GX1

["Marco Tralli" <marco.tralli@snapon.com>]

Hello all,

I have random hangs on kernel boot or after few minutes on a NatSemi Geode
GX1 based PC-104 (from Advantech) using kernel 2.6.23-rc6. The system locks,
no way to use SysRq key, no usefull logs.

No problems using kernel 2.6.21 series that I was using before with same
config options.

I found that commenting out "geode_configure" call in
arch/i386/kernel/cpu/cyrix.c the problem is fixed.

I guess recent changes to cyrix.c that replace macros setCx86/getCx86 with
inlined functions have now "activate" performance tricks in geode_configure
code that previously were "inactive" due to wrong macro espansion. So not
only "Suspend on Halt" function is enabled but also less or not documented
geode tricks (incrementor margin, fast fpu, write-back) now broken on some
GX1/GXm platform (maybe because of BIOS?)

I can further investigate on what exact geode_configure part cause my hangs,
but I suggest to make a config options to explicity enable Geode performance
tricks only if requested (maybe using CONFIG_MGEODEGX1) .

Regards
Marco Tralli
Snap-on Equipment


processor : 0
vendor_id : CyrixInstead
cpu family : 5
model  : 9
model name : Geode(TM) Integrated Processor by National Semi
stepping : 2
cpu MHz  : 299.239
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 : 596.37