2.4.31 panics on boot on 486 box: TSC requires pentium

2.4.31 panics on boot on 486 box: TSC requires pentium

[johsc]

2.4.31 compiled with -m486, panics on boot (486DX) and says something about
TSC requires pentium, bang.
enabling the obscure flag

 [*] Unsynced TSC support

seems to fix this - the corresponding .config label name is actually *more*
helpful than the documentation.


- Obscure-sound-bug
jazz16 on Travelmate 4000M doesn't seem to work either, sb.o 
complains about DSP version being "only" 3.01.

(#insmod sb type=10 io=0x220 irq={5,7} dma=1 dma16=7)

there is sound but mpg123 says 44100 is impossible.

Re: 2.4.31 panics on boot on 486 box: TSC requires pentium

[Willy Tarreau]

On Tue, Jul 26, 2005 at 08:22:58PM +0200, johsc@arcor.de wrote:
> 2.4.31 compiled with -m486, panics on boot (486DX) and says something about
> TSC requires pentium, bang.

The processor type is wrong, you're on at least a pentium instead of a 486.
If you changed the config by hand (vi .config), you must do "make oldconfig"
after, to propagate values along the options.

> enabling the obscure flag
> 
>  [*] Unsynced TSC support
>
> seems to fix this - the corresponding .config label name is actually *more*
> helpful than the documentation.

Seems to me that it simply disables use of TSC. But if you see this option,
it means that your kernel has been compiled with SMP enabled, which is not
possible on 486 (I may be wrong here). Most probably, you took a config from
an inadequate kernel for your machine.

> - Obscure-sound-bug
> jazz16 on Travelmate 4000M doesn't seem to work either, sb.o 
> complains about DSP version being "only" 3.01.
> 
> (#insmod sb type=10 io=0x220 irq={5,7} dma=1 dma16=7)
> 
> there is sound but mpg123 says 44100 is impossible.

mpg123 requires at least around 486 DX4-100 to play mp3 at 44100, so
perhaps it fails a self-test and complains because of that ?

Willy

Re: 2.4.31 panics on boot on 486 box: TSC requires pentium

[Maciej W. Rozycki]

On Wed, 27 Jul 2005, Willy Tarreau wrote:

> Seems to me that it simply disables use of TSC. But if you see this option,
> it means that your kernel has been compiled with SMP enabled, which is not
> possible on 486 (I may be wrong here). Most probably, you took a config from
> an inadequate kernel for your machine.

 We do support SMP on Intel MP compliant 486 systems, i.e. as long as they 
are based on the APIC architecture and have a correct MP-table.  This 
might have not been tested for long if at all, though.

  Maciej

Re: 2.4.31 panics on boot on 486 box: TSC requires pentium

[Mikael Pettersson]

On Tue, 26 Jul 2005 20:22:58 +0200, johsc@arcor.de wrote:
>2.4.31 compiled with -m486, panics on boot (486DX) and says something about
>TSC requires pentium, bang.
>enabling the obscure flag
>
> [*] Unsynced TSC support
>
>seems to fix this - the corresponding .config label name is actually *more*
>helpful than the documentation.

Let me guess: you started from the default config and just flipped
the CPU option to 486? That doesn't work in 2.4 kernels, since it
leaves the derived "I have TSC" option enabled.

A second configuration round (make oldconfig for example) fixes this.
grep TSC .config to ensure it's not set before compiling.