Hello all.
I'm getting a kernel panic from my 2.4.22 kernel when compiled for
i486 (see attached .config).
"Kernel panic: Kernel compiled for Pentium+, requires TSC feature!"
The CPU is a Cyrix Cx486DX2 100MHz part. I tried booting with notsc
but I get the message:
"notsc: Kernel compiled with CONFIG_X86_TSC, cannot disable TSC."
The kernel will work fine when recompiled for i386.
Does a real 486 have a TSC, or is this a config bug?
--
(o- Chris Sykes -- GPG Key: http://www.sigsegv.plus.com/key.txt
//\ "Don't worry. Everything is getting nicely out of control ..."
V_/_ Douglas Adams - The Salmon of Doubt
Chris Sykes writes:
> I'm getting a kernel panic from my 2.4.22 kernel when compiled for
> i486 (see attached .config).
>
> "Kernel panic: Kernel compiled for Pentium+, requires TSC feature!"
>
> The CPU is a Cyrix Cx486DX2 100MHz part. I tried booting with notsc
> but I get the message:
> "notsc: Kernel compiled with CONFIG_X86_TSC, cannot disable TSC."
>
> The kernel will work fine when recompiled for i386.
>
> Does a real 486 have a TSC, or is this a config bug?
...
> CONFIG_M486=y
...
> CONFIG_X86_TSC=y
I've reproduced this problem. It's a bug in the configuration
system which triggers when you change an option which has
derived options.
In this case, when first configuring for a CPU with TSC the
derived CONFIG_X86_TSC option is added. Then when reconfiguring
for a TSC-less CPU (e.g., 486) the derived option stays because
it derived from something that _was_ defined at the start of the
config run.
The workaround is to do an additional 'make oldconfig', after
which the derived option will be gone.
/Mikael
On Fri, Sep 26, 2003 at 01:40:28PM +0200, Mikael Pettersson wrote:
> system which triggers when you change an option which has
> derived options.
>
> In this case, when first configuring for a CPU with TSC the
> derived CONFIG_X86_TSC option is added. Then when reconfiguring
> for a TSC-less CPU (e.g., 486) the derived option stays because
> it derived from something that _was_ defined at the start of the
> config run.
>
> The workaround is to do an additional 'make oldconfig', after
> which the derived option will be gone.
OK. Thanks for the info.
--
(o- Chris Sykes -- GPG Key: http://www.sigsegv.plus.com/key.txt
//\ "Don't worry. Everything is getting nicely out of control ..."
V_/_ Douglas Adams - The Salmon of Doubt