Re: Cyrix 6x86MX and Centaur C6 CPUs in 2.1.102

Phil's Kernel Account (
Tue, 19 May 1998 00:15:44 -0400 (EDT)

On Mon, 18 May 1998, Vojtech Pavlik wrote:

#*sigh* And this would also mean that my joystick driver will fallback into
#PIT timing mode on a Cyrix, though it could safely use the TSC timer, since
#there isn't a chance of the CPU getting a HLT instruction while it is timing
#the joystick input ...

Thank you SO much Vojtech. I've been trying to remember something that
REALLY relies on the TSC to support my suggestion all day. Now I can reply
to Linus' mail! Yay! }:)

#If I could suggest a solution, add a bug flag for this behaviour, and check
#for presence of TSC and absence of the bug in do_fast_gettimeofday. The TSC
#simply is there, though not suitable for all uses.

Perhaps, perhaps not. There IS a way to address it correctly in ALL
situations, I just don't remember it.

#Also, it'd be neat if the kernel had some public variable containing the
#real TSC increment speed for each CPU, say in ticks per second or
#microsecond, so that drivers using the TSC wouldn't need to calibrate it.

Oooo, that WOULD be *VERY* handy. Instant-sync. I like. :)

-Phil R. Jaenke ( /
TheGuyInCharge(tm), Ketyra Designs - We get paid to break stuff :)
Linux pkrea.ketyra.INT 2.0.33 #15 Sat Apr 18 00:40:21 EDT 1998 i586
Linux 2.0.33 #15 Fri Apr 17 00:22:13 EDT 1998 i586
- Linus says for 'brave people only.' I say 'keep a backup.' - :)

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